Polymers for use as protective layers and other components in electrochemical cells

ABSTRACT

Electrode structures and electrochemical cells are provided. The electrode structures and/or electrochemical cells described herein may include one or more protective layers comprising a polymer layer and/or a gel polymer electrolyte layer. The polymer layer may be formed from the copolymerization of an olefinic monomer comprising at least one electron withdrawing group and an olefinic comonomer comprising at least one electron donating group. Methods for forming polymer layers are also provided.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application Ser. No. 61/721,941, entitled, “Polymers for Useas Protective Layers and Other Components in Electrochemical Cells,”filed on Nov. 2, 2012, and to U.S. Provisional Application Ser. No.61/790,879, entitled, “Polymers for Use as Protective Layers and OtherComponents in Electrochemical Cells”, filed on Mar. 15, 2013, each ofwhich is incorporated herein by reference in its entirety for allpurposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

This invention was made with government support under Grant No.DE-AR0000067 awarded by the Department of Energy ARPA-E program (ARPA-EBEEST DE-FOA-00000207-1536). The government has certain rights in theinvention.

FIELD OF INVENTION

The present invention relates to polymers for use as protective layersfor electrode structures and/or other components in electrochemicalcells.

BACKGROUND

A typical electrochemical cell has a cathode and an anode whichparticipate in an electrochemical reaction. Some electrochemical cells(e.g., rechargeable batteries) may undergo a charge/discharge cycleinvolving stripping and deposition of metal (e.g., lithium metal) on thesurface of the anode accompanied by parasitic reactions of the metal onthe anode surface with other cell components (e.g., electrolytecomponents), wherein the metal can diffuse from the anode surface duringdischarge. The efficiency and uniformity of such processes can affectefficient functioning of the electrochemical cell. In some cases, one ormore surfaces of one or more electrodes may become uneven as theelectrochemical cell undergoes repeated charge/discharge cycles, oftendue to uneven redeposition of a reduced ion dissolved in theelectrolyte. The roughening of one or more surfaces of one or moreelectrodes can result in increasingly poor cell performance.

Despite the various approaches proposed for forming electrodes andforming interfacial and/or protective layers, improvements are needed.

SUMMARY OF THE INVENTION

The present invention relates to electrode structures, and morespecifically, to protective layers or other components (e.g., polymergel layers or separators) for use in electrochemical cells.Electrochemical cells and other articles including such layers orcomponents are also provided. The subject matter of the presentinvention involves, in some cases, interrelated products, alternativesolutions to a particular problem, and/or a plurality of different usesof one or more systems and/or articles.

In one set of embodiments, an electrochemical cell is provided. In oneembodiment, an electrochemical cell includes an electroactive layer andat least one polymer layer. The polymer layer is formed from thecopolymerization of an olefinic monomer comprising at least one electronwithdrawing group and an olefinic comonomer comprising at least oneelectron donating group.

In another embodiment, an electrochemical cell includes an electroactivelayer and at least one polymer layer. The polymer layer is formed fromthe polymerization of an olefinic monomer having at least one electronwithdrawing group and at least one electron donating group.

In another embodiment, an electrochemical cell includes an electroactivelayer and at least one polymer layer. The at least one polymer layer isformed by copolymerization of a maleimide and a vinyl ether.

In another embodiment, an electrochemical cell comprises anelectroactive layer and at least one layer comprising a polymer. Thepolymer is formed from: a) the copolymerization of at least one olefinicmonomer comprising at least one electron withdrawing group attached to adouble bond and at least one olefinic comonomer comprising at least oneelectron donating group attached to a double bond, or b) thepolymerization of an olefinic monomer having at least two double bonds,at least one electron withdrawing group attached to one of the doublebonds, and at least one electron donating group attached to another ofthe double bonds. The polymer includes structural units comprising theat least one electron withdrawing group that alternate with structuralunits comprising the at least one electron donating group.

In some embodiments involving the electrochemical cells described aboveand herein, the electron withdrawing group is selected from the groupconsisting of a haloalkyl, —CN, —COOR₁, —C(═O)R₁, —CON(R₁)₂, —CONR₁H,halogen, —NO₂, —SO₃R₁, —SO(OR₁)₂, —SO(OR₁)H, —SOR₁, —SO₂R₁, —PO(OR₁)₂,—PO(OR₁)H, and protonated amine groups, wherein two electron withdrawinggroups attached in the 1,2-position to the double bond may form togetherwith the double bond of a 5- to 6-membered substituted or unsubstituted,unsaturated cycle or heterocycle. Each occurrence of R₁ is independentlyselected from the group consisting of hydrogen; halogen; substituted orunsubstituted, branched or unbranched aliphatic; substituted orunsubstituted cyclic; substituted or unsubstituted, branched orunbranched acyclic; substituted or unsubstituted, branched or unbranchedheteroaliphatic; substituted or unsubstituted, branched or unbranchedacyl; substituted or unsubstituted aryl; substituted or unsubstitutedheteroaryl, substituted or unsubstituted, branched or unbranchedalkylene oxide or poly(alkylene oxide); a metal ion, an anionic group,and a lithium-containing group. R₁ may be linked to at least one furtherelectron donating or electron withdrawing group attached to an olefinicdouble bond.

Additionally, in some embodiments involving the electrochemical cellsdescribed above and herein, the electron donating group is selected fromthe group consisting of an alkylamino, a heteroaryl, a cycloalkyl, acycloalkenyl, a cycloalkynyl, —OCOR₂, —NR₂COR₂, —OR₂, —SR₂, —Si(OR₂)₃,—Si(OR₂)₂H, —Si(OR₂)H₂, —Si(R₂)₃, —Si(R₂)₂H, —Si(R₂)H₂,

wherein each occurrence of R₂ is independently selected from the groupconsisting of hydrogen; substituted or unsubstituted, branched orunbranched aliphatic; substituted or unsubstituted cyclic; substitutedor unsubstituted, branched or unbranched acyclic; substituted orunsubstituted, branched or unbranched heteroaliphatic; substituted orunsubstituted, branched or unbranched acyl; substituted or unsubstitutedaryl; substituted or unsubstituted heteroaryl, substituted orunsubstituted, branched or unbranched alkylene oxide or poly(alkyleneoxide); a metal ion; an anionic group, and a lithium-containingconducting group, and wherein n is 1, 2 or 3. R₂ may optionally belinked to at least one further electron donating or electron withdrawinggroup attached to an olefinic double bond.

In certain embodiments involving the electrochemical cells describedabove and herein, at least one of the olefinic monomers comprises atleast two double bonds, wherein each double bond has attached theretoone or more electron donating groups or one or more electron withdrawinggroups.

In certain embodiments involving the electrochemical cells describedabove and herein, the polymer is formed by copolymerization of at leastone maleimide or maleic anhydride and at least one vinyl ether. In otherembodiments, the polymer is formed by polymerization of an olefinicmonomer including at least one maleimide or maleic anhydride and atleast one vinyl ether.

In certain embodiments involving the electrochemical cells describedabove and herein, the olefinic monomer comprising the at least oneelectron withdrawing group is selected from the group consisting of

In certain embodiments involving the electrochemical cells describedabove and herein, the electron withdrawing group and/or the electrondonating group comprises a cycloalkyl group, a cycloalkenyl group, or acycloalkynyl group. In other embodiments, the electron withdrawing groupand/or the electron donating group comprises a heteroaryl group;optionally, wherein the heteroaryl group comprises a nitrogenheteroatom, two nitrogen heteroatoms, or an oxygen heteroatom.

In certain embodiments involving the electrochemical cells describedabove and herein, the polymer comprises a substituted or unsubstituted,branched or unbranched poly(alkylene oxide); an anionic group; and/or alithium-containing group; optionally, wherein the lithium-containinggroup is Aryl-SO₃Li or Alkyl-SO₃Li.

In some embodiments, R₁ and/or R₂ comprises a lithium ion and/or isconductive to lithium ions.

In some instances, the electroactive layer comprises an alkali metal(e.g., lithium metal).

In certain embodiments involving the electrochemical cells describedabove and herein, the Q-e scheme of the monomer comprising the at leastone electron withdrawing group attached to the double bond is e>0 andQ<0.1 and the Q-e scheme of the comonomer comprising the at least oneelectron donating group attached to the double bond is e<0 a and Q>0.1.In other embodiments, the Q-e scheme of the monomer comprising the atleast one electron withdrawing group attached to the double bond is e>0and Q>0.1 and the Q-e scheme of the comonomer comprising the at leastone electron donating group attached to the double bond is e<0 a andQ<0.1.

In certain embodiments involving the electrochemical cells describedabove and herein, a dry conductivity of the layer comprising the polymeris greater than 10⁻¹⁰ and less than or equal to 10⁻⁴ S/cm at roomtemperature.

In certain embodiments involving the electrochemical cells describedabove and herein, the layer comprising the polymer is a gel polymerelectrolyte layer. In some embodiments, a conductivity of the gelpolymer electrolyte layer is greater than 10⁻⁷ and less than or equal to10⁻³ S/cm at room temperature when swollen by an electrolyte. In somecases, the gel polymer electrolyte layer is swollen with an electrolytecomprising at least one of dioxolane and dimethoxyethane.

In certain embodiments involving the electrochemical cells describedabove and herein, the electrochemical cell further comprises an ionconductive layer disposed between the electroactive layer and the layercomprising the polymer. In some embodiments, the electrochemical cellfurther comprises alternating layers of the at least one layercomprising the polymer and at least one ion conductive layer. In certainembodiments, the ion conductive layer comprises at least one of lithiumnitride, lithium silicate, lithium borate, lithium aluminate, lithiumphosphate, lithium phosphorus oxynitride, lithium silicosulfide, lithiumgermanosulfide, lithium oxides, lithium lanthanum oxides, lithiumtitanium oxides, lithium borosulfide, lithium aluminosulfide, andlithium phosphosulfide.

In certain embodiments involving the electrochemical cells describedabove and herein, the polymer further comprises a second comonomeradapted to tether the polymer to a substrate. In certain embodiments,the polymer comprises approximately 0.1 molar % to 20 molar % of thesecond comonomer. In some instances, the second comonomer comprises atleast one of carboxylic acid, carboxylate, glycidyl, maleic anhydride,phosphonic acid ester, sulfonic acid, and sulfonic acid esters.

In certain embodiments involving the electrochemical cells describedabove and herein, the polymer comprises excess vinyl ether compared tomaleimide, and the excess vinyl ether acts as a plasticizer.

In certain embodiments involving the electrochemical cells describedabove and herein, the polymer (or monomer(s)) comprises a lithium salt.In some embodiments, the lithium salt is intrinsic to the polymer. Inother embodiments, the lithium salt is dissolved in an electrolyte to beused with the electrochemical cell. In yet other embodiments, thelithium salt is intrinsic to the polymer and is dissolved in anelectrolyte to be used with the electrochemical cell. In someembodiments, the lithium salt comprises at least one of LiTFSI, LiFSI,LiI, LiPF₆, LiAsF₆, LiBOB and derivatives thereof.

In certain embodiments involving the electrochemical cells describedabove and herein, the polymer further comprises a spacer grouppositioned between the electron withdrawing group and electron donatinggroup.

In certain embodiments involving the electrochemical cells describedabove and herein, the molar ratio of double bonds attached to anelectron withdrawing group monomer to double bonds attached to anelectron donating group is approximately one to one.

In certain embodiments involving the electrochemical cells describedabove and herein, at least one of the monomer and comonomer, or theolefinic monomer having at least two double bonds, comprises at leastone functional group selected from the group consisting of poly(ethyleneoxide), lithiated sulfonate groups, lithiated carboxylate groups, andlithiated trifluoromethanesulfonylimide groups. In some embodiments, atleast one of the monomer and comonomer, or to the olefinic monomerhaving at least two double bonds, comprises poly(ethylene oxide).

In certain embodiments involving the electrochemical cells describedabove and herein, the electrochemical cell further comprises a cathodecomprising sulfur as an active cathode species. In certain embodiments,the electrochemical cell is a lithium metal battery. In otherembodiments, the electrochemical cell is a lithium ion battery.

In one set of embodiments, a series of methods for forming a componentfor use in an electrochemical cell is provided. In one embodiment, amethod for forming a component for use in an electrochemical cellincludes: providing an electroactive layer; depositing an olefinicmonomer comprising at least one electron withdrawing group and anolefinic comonomer comprising at least one electron donating group on asurface; and polymerizing the monomer and comonomer using a free radicalmechanism to form a polymer layer.

In another embodiment, a method for forming a component for use in anelectrochemical cell includes: providing an electroactive layer;depositing a monomer comprising a maleimide and a comonomer comprising avinyl ether on a surface; and polymerizing the monomer and comonomerusing a free radical mechanism to form a polymer layer.

In another embodiment, a method for forming a component for use in anelectrochemical cell comprises providing an electroactive layer, anddepositing onto a surface: a) an olefinic monomer comprising at leastone electron withdrawing group attached to a double bond and at leastone olefinic comonomer comprising at least one electron donating groupattached to a double bond, or b) an olefinic monomer having at least twodouble bonds, at least one electron withdrawing group attached to one ofthe double bonds, and at least one electron donating group attached toanother of the double bonds. The method involves polymerizing themonomer(s) using a free radical mechanism to form a polymer layer.

In certain embodiments involving the method(s) described above andherein, the olefinic monomer comprising the at least one electronwithdrawing group comprises a maleimide or maleic anhydride and thecomonomer comprising the at least one electron donating group comprisesa vinyl ether. In other embodiments, the olefinic monomer having atleast two double bonds comprises at least one maleimide or maleicanhydride and at least one vinyl ether.

In certain embodiments involving the method(s) described above andherein, the electron withdrawing group is selected from the groupconsisting of a haloalkyl, —CN, —COOR₁, —C(═O)R₁—CON(R₁)₂, —CONR₁H,halogen, —NO₂, —NR₁OR₁, SO₃R₁, —SO(OR₁)₂, —SO(OR₁)H, —SOR₁, —SO₂R₁,—PO(OR₁)₂, —PO(OR₁)H, and protonated amine groups, wherein two electronwithdrawing groups attached in the 1,2-position to the double bond mayform together with the double bond of a 5- to 6-membered substituted orunsubstituted, unsaturated cycle or heterocycle. Each occurrence of R₁is independently selected from the group consisting of hydrogen;halogen; substituted or unsubstituted, branched or unbranched aliphatic;substituted or unsubstituted cyclic; substituted or unsubstituted,branched or unbranched acyclic; substituted or unsubstituted, branchedor unbranched heteroaliphatic; substituted or unsubstituted, branched orunbranched acyl; substituted or unsubstituted aryl; substituted orunsubstituted heteroaryl, substituted or unsubstituted, branched orunbranched alkylene oxide or poly(alkylene oxide); a metal ion; ananionic group, and a lithium-containing group. R₁ may be linked to atleast one further electron donating or electron withdrawing groupattached to an olefinic double bond.

Additionally, in certain embodiments involving the method(s) describedabove and herein, the electron donating group comprises at least onegroup selected from the group consisting of an alkylamino, a heteroaryl,a cycloalkyl, a cycloalkenyl, a cycloalkynyl, —OCOR₂, —NR₂COR₂, —OR₂,—SR₂, —Si(OR₂)₃, —Si(OR₂)₂H, —Si(OR₂)H₂, —Si(R₂)₃, —Si(R₂)₂H, —Si(R₂)H₂,

and wherein each occurrence of R₂ is independently selected from thegroup consisting of hydrogen; substituted or unsubstituted, branched orunbranched aliphatic; substituted or unsubstituted cyclic; substitutedor unsubstituted, branched or unbranched acyclic; substituted orunsubstituted, branched or unbranched heteroaliphatic; substituted orunsubstituted, branched or unbranched acyl; substituted or unsubstitutedaryl; substituted or unsubstituted heteroaryl; substituted orunsubstituted, branched or unbranched alkylene oxide or poly(alkyleneoxide); a metal ion; an anionic group; and a lithium-containing group,wherein n is 1, 2 or 3. R₂ may optionally be linked to at least onefurther electron donating or electron withdrawing group attached to anolefinic double bond.

In certain embodiments involving the method(s) described above andherein, depositing the monomer comprises using at least one of doctorblading, spray coating, spin coating, solution casting, and vapordeposition. In other embodiments, flash evaporation is used.

In certain embodiments involving the method(s) described above andherein, polymerizing comprises applying at least one of UV light, anelectron beam, or thermal energy to the monomer and comonomer, or to theolefinic monomer having at least two double bonds, to activate the freeradical mechanism. In some cases, polymerizing comprises polymerizingthe monomers within less than or equal to 5 seconds, less than or equalto 3 seconds, or less than or equal to 1 second.

In certain embodiments involving the method(s) described above andherein, the method involves forming an ion conductive layer on theelectroactive layer. In some cases, the ion conductive layer ispositioned between the electroactive layer and the layer comprising thepolymer.

In certain embodiments, depositing the monomer and the comonomer on thesurface further comprises depositing the monomer and the comonomer on asurface of the electroactive layer, or on a surface of the ionconductive layer.

In certain embodiments, depositing the olefinic monomer having at leasttwo double bonds on the surface further comprises depositing theolefinic monomer on a surface of the electroactive layer, or on asurface of the ion conductive layer.

Other aspects, embodiments and features of the invention will becomeapparent from the following detailed description when considered inconjunction with the accompanying drawings. The accompanying figures areschematic and are not intended to be drawn to scale. For purposes ofclarity, not every component is labeled in every figure, nor is everycomponent of each embodiment of the invention shown where illustrationis not necessary to allow those of ordinary skill in the art tounderstand the invention. All patent applications and patentsincorporated herein by reference are incorporated by reference in theirentirety. In case of conflict, the present specification, includingdefinitions, will control.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present invention will be described byway of example with reference to the accompanying figures, which areschematic and are not intended to be drawn to scale. In the figures,each identical or nearly identical component illustrated is typicallyrepresented by a single numeral. For purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment of the invention shown where illustration is not necessary toallow those of ordinary skill in the art to understand the invention. Inthe figures:

FIG. 1 shows an article for use in an electrochemical cell according toone set of embodiments;

FIG. 2A shows an electrode including an electroactive layer and apolymer layer according to one set of embodiments;

FIG. 2B shows an electrode including an electroactive layer a multilayerprotective structure according to one set of embodiments; and

FIG. 3 shows an electrochemical cell according to one set ofembodiments.

DETAILED DESCRIPTION

Polymer compositions, and more specifically, polymer compositions foruse in electrochemical cells, are provided. The disclosed polymercompositions may be formed from the copolymerization of at least oneolefinic monomer comprising at least one electron withdrawing groupattached to a double bond and at least one olefinic comonomer comprisingat least one electron donating group attached to a double bond. In otherembodiments, the disclosed polymer compositions may be formed from thepolymerization of an olefinic monomer possessing at least two doublebonds. In some cases, at least one electron withdrawing group isattached to one of the double bonds, and at least one electron donatinggroup attached to another of the double bonds. In certain instances,each double bond of an olefinic monomer has attached thereto one or moreelectron donating groups or one or more electron withdrawing groups. Theresulting polymer may include structural units comprising the at leastone electron withdrawing group that alternate with structural unitscomprising the at least one electron donating group. Depending upon theparticular embodiment, the monomer and/or comonomer may include, in somecases, a maleimide. The monomers may be polymerized via a free radicalshift mechanism. The polymerization reaction may be initiated by, forexample, UV light, an electron beam, or thermal energy dependent uponthe particular free radical mechanism.

The disclosed polymer compositions may be incorporated into electrodestructures described herein. For example, the electrode structures mayinclude one or more polymer layers, e.g., in a multi-layered structure.The multi-layered structure may include one or more ion conductivelayers and one or more polymer layers comprising the polymers disclosedherein disposed adjacent to the one or more ion conductive layers. Theresulting structures may be highly conductive to electroactive materialions and may protect the underlying electroactive material surface fromreaction with components in the electrolyte. In another set ofembodiments, an electrochemical cell may include a gel polymerelectrolyte layer comprising the disclosed polymer compositions. In somecases, such protective layers and/or gel polymer layers may be suitablefor use in an electrochemical cell including an electroactive materialcomprising lithium (e.g., metallic lithium).

As described herein, in some embodiments, a disclosed polymercomposition may be formed from the copolymerization of a monomer havingan electron withdrawing group and a comonomer having an electrondonating group. For instance, copolymerization may involve at least oneolefinic monomer comprising at least one electron withdrawing groupattached to a double bond and at least one olefinic comonomer comprisingat least one electron donating group attached to a double bond. Theinventors have recognized the benefits associated with using a polymerbased on such copolymerization. For example, an olefinic monomer havingat least one electron withdrawing group and an olefinic comonomer havingat least one electron donating group may enable the production of fast,radically-curable polymer films for use in an electrochemical cell.Furthermore, the resulting polymers may have good mechanical andchemical stability in the associated electrochemical cells, andespecially for lithium-sulfur based systems. In certain embodiments, thedisclosed polymer may be incorporated into the electrochemical cell as aprotective layer on various components, a polymer gel electrolyte, aseparator, and/or any other appropriate application with anelectrochemical cell. Therefore, the current disclosure should be viewedgenerally as disclosing the use of the currently described polymers withan electrochemical cell, and should not be limited to only the specificconstructions disclosed herein.

With regards to the polymerization of the currently described polymers,the polymerization reaction between the monomer and comonomer, or thepolymerization reaction between the olefinic monomers having two doublebonds, may advantageously be initiated by a free radical mechanism.Thus, the polymerization reaction may be initiated by, for example, UVlight, an electron beam, thermal energy, or any other appropriate energysource. This may be particularly advantageous in the context of use inan electrochemical cell since the polymerization reaction may beconducted at a temperature below a degradation temperature and/ormelting temperature of the associated electroactive layers and/orcomplements within the electrochemical cell. Furthermore, by selectingspecific functional groups the reaction kinetics may be tailored toprovide a relatively fast curing time, e.g., on the order of severalseconds. For example, the polymerization reaction may occur within lessthan or equal to 5 seconds, less than or equal to 3 seconds, or lessthan or equal to 1 second.

Furthermore, in some embodiments, the methods described herein mayenable the inclusion of ionic compounds (i.e., salts) in the disclosedcompositions. For example, in some embodiments, lithium salts may beadvantageously included in a polymer layer in relatively high amounts.Inclusion of the lithium and/or other salts may increase the ionconductivity of the material. Increases in the ion conductivity of thematerial may enable enhanced ion diffusion between associated anodes andcathodes within an electrochemical cell. Therefore, inclusion of thesalts may enable increases in specific power available from anelectrochemical cell and/or extend the useful life of an electrochemicalcell due to the increased diffusion rate of the ion speciestherethrough.

Moreover, in certain embodiments, the compositions described herein canbe formed using flash evaporation methods, which may enable theincorporation of salts in the composition. The monomer (and optionalcomonomer(s)) described herein may also be chosen to be compatible withflash evaporation methods. For example, in some embodiments, in additionto possessing mechanical stability and chemical stability within thecomponents in the final electrochemical cell, to be suitable for flashevaporation methods, the monomer (and optional comonomer) may need to beable to evaporate and condense while in high vacuum. Therefore, monomers(and optional comonomers) with vapor pressures suitable for use withflash evaporation methods may be specifically used to enable thismanufacturing method. In addition to the above, it may also be desirablethat the monomer and optional comonomer undergo copolymerization via aradical copolymerization process (e.g., on the order of seconds)combined with a flash evaporation method.

Depending upon the intended use, in some embodiments, the monomer andcomonomer may both exhibit intrinsic ionic conductivity, only one mayexhibit intrinsic ionic conductivity, or neither may exhibit intrinsicionic conductivity. For example, without wishing to be bound by theory,when used in the dry state, at least one of the monomers may exhibitintrinsic ionic conductivity to provide ion transport. For instance, atleast one of the monomers, and therefore the resulting polymer, mayinclude one or more lithium-containing groups (e.g., lithium salts).Optionally, one or more lithium-containing groups may be added tofurther enhance ion conductivity of the polymer. In other embodiments,the resulting polymer is intrinsically non-ionically conductive, and oneor more lithium-containing groups are added to the resulting polymer toenhance the polymer's lithium ion conductivity in the dry state. In someembodiments, the one or more lithium-containing groups (e.g., lithiumsalts) added to the polymer is/are the same lithium-containing groups(e.g., lithium salts) present in the solvent/electrolyte to be used withthe electrochemical cell. However, in other embodiments, differentlithium-containing groups may be used in the polymer and thesolvent/electrolyte.

Alternatively, when used in the swollen state, both the monomer andcomonomer may be non-ionically conductive since ion transport can beprovided by the solvent/electrolyte (which may containlithium-containing groups in the form of dissolved salts). Embodimentsin which only one of the monomer and comonomer, or both the monomer andcomonomer, are intrinsically ionically conductive are also possible. Incertain embodiments, at least one of the monomers (and therefore theresulting polymer) includes one or more lithium-containing groups andone or more lithium-containing groups are added to the polymer in theswollen state (e.g., via the solvent/electrolyte) to enhance thepolymer's lithium-ion conductivity.

Such combinations of intrinsic ionic conductivity (or non-ionicconductivity) of the monomer(s) (and resulting polymer) and the presence(or absence) of lithium-containing groups are also possible forembodiments in which a monomer having both electron withdrawing groupsand electron donating groups, as well as at least two double bonds, isused to form the polymer.

In yet another embodiment, the polymerization of the monomers describedherein may result in a polymer that is more stable to hydrolysis andother reactions with polysulfides in lithium-sulfur batteries comparedto certain existing polymers (e.g., polyacrylates).

As noted above, the currently described polymers may be formed from thecopolymerization of two different monomers separately functionalizedwith an electron withdrawing group and an electron donating group. Inembodiments where separate monomers are used to provide the electronwithdrawing group and electron donating group, a first structural unit(e.g., repeat unit) may correspond to the monomer incorporating theelectron withdrawing group. Similarly, a second structural unit (e.g.,repeat unit) may correspond to the monomer incorporating the electrondonating group. On subsequent polymerization, a resulting polymer chainmay have the formula -[Structural Unit 1]_(n)-[Structural Unit 2]_(m)-,where n and m are integers greater than 2. Depending upon the specificmonomers selected, the structural units (e.g., repeat units) may bearranged in a pattern corresponding to a block copolymer, a randomcopolymer, and/or an alternating copolymer having varying lengths andmolecular weights. As described herein, in some cases at least oneolefinic monomer comprises at least one electron withdrawing groupattached to a double bond, and at least one olefinic comonomer comprisesat least one electron donating group attached to a double bond. In someembodiments, the resulting polymer includes structural units comprisingthe at least one electron withdrawing group that alternate withstructural units comprising the at least one electron donating group.The resulting polymer may be branched, or unbranched. In someembodiments, the resulting polymer is crosslinked.

It should be appreciated that while each of the monomer or comonomer mayinclude an electron withdrawing group and/or an electron donating groupin some embodiments, in other embodiments the corresponding structuralunit (e.g., repeat unit) in the resulting polymer may not include suchan electron withdrawing group or an electron donating group, since theelectron withdrawing group or an electron donating group of the monomermay undergo a reaction upon polymerization.

While separate monomers including the electron withdrawing groups andelectron donating groups have been disclosed, the current disclosure isnot limited in this fashion. For example, in certain embodiments, thepolymer may be formed from a hybrid monomer functionalized with both anelectron withdrawing group and an electron donating group as describedin more detail below. In such an embodiment, the polymer may be formedfrom a single structural unit (e.g., repeat unit) derived from thehybrid monomer. In another example, additional structural units may bepresent in a composition, such as -[Structural Unit 1]_(n)-[StructuralUnit 2]_(m)-[Structural Unit 3]_(p)-, where the third structural unitmay include an electron withdrawing group, an electron donating group,or a compound absent an electron withdrawing group or an electrondonating group. A structural unit having neither an electron withdrawinggroup nor an electron donating group may, for example, improve a desiredproperty of the resulting polymer or the processability of the resultingpolymer. Other configurations of structural units are also possible.

In some embodiments, each of n and m may be, independently, greater thanor equal to approximately 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50,60, 70, or any other suitable value. Further, each of n and m may be,independently, less than or equal to approximately 100, 90, 80, 70, 60,50, 40, 30, 20, 10, 9, 8, 7, 6, 5, or any other suitable value. Forexample, each of n and m may be, independently, between approximately 1and 100 in some embodiments, or between approximately 1 and 10 in otherembodiments. Other combinations of the above-referenced ranges are alsopossible. In some embodiments, n and m are approximately equal, thoughother embodiments in which they are unequal are also possible. Incertain embodiments, p is less each of n and m. In some cases, p is afraction of n+m. For example, p may be less than or equal toapproximately 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%,2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any other suitable fraction of,n+m. For example, in one embodiment, p is between approximately 0.1% toapproximately 10% of n+m.

In some embodiments, the average molecular weight (MO of themonomer/comonomer may be greater than or equal to approximately 100g/mol, 150 g/mol, 200 g/mol, 250 g/mol, 300 g/mol, 400 g/mol, 500 g/mol,600 g/mol, 700 g/mol, 800 g/mol, 900 g/mol, 1000 g/mol, 1100 g/mol, 1200g/mol, 1300 g/mol, 1400 g/mol, 1500 g/mol, 1800 g/mol, or any othersuitable molecular weight. Further, the molecular weight of the monomermay be less than approximately 2000 g/mol, 1900 g/mol, 1800 g/mol, 1700g/mol, 1600 g/mol, 1500 g/mol, 1400 g/mol, 1300 g/mol, 1200 g/mol, 1100g/mol, 1000 g/mol, 900 g/mol, 800 g/mol, 700 g/mol, 600 g/mol, 500g/mol, or any other appropriate molecular weight. Combinations of theabove are possible (e.g., a molecular weight of approximately 100 g/molto approximately 2000 g/mol, approximately 100 g/mol to approximately1000 g/mol, or approximately 150 g/mol to approximately 500 g/mol).Other combinations are also possible.

In some embodiments, the average molecular weight (e.g., number averagemolecular weight, M_(n)) of the resulting polymer may be greater than orequal to approximately 1000 g/mol, 5000 g/mol, 10,000 g/mol, 15,000g/mol, 20,000 g/mol, 50,000 g/mol, 100,000 g/mol, 200,000 g/mol, 300,000g/mol, 400,000 g/mol, 500,000 g/mol, 1,000,000 g/mol, 2,000,000 g/mol,3,000,000 g/mol, 4,000,000 g/mol, or any other appropriate molecularweight. Further, the molecular weight of the resulting polymer may beless than approximately 5,000,000 g/mol, 4,000,000 g/mol, 3,000,000g/mol, 2,000,000 g/mol, 1,000,000 g/mol, 500,000 g/mol, 400,000 g/mol,300,000 g/mol, 200,000 g/mol, 100,000 g/mol, 50,000 g/mol, 20,000 g/mol,15,000 g/mol, 10,000 g/mol, 5000 g/mol, or any other appropriatemolecular weight. Combinations of the above are possible (e.g. amolecular weight of approximately 1000 g/mol to approximately 5,000,000g/mol or approximately 5000 g/mol to approximately 20,000 g/mol). Othercombinations are also possible. The molecular weight can be determinedby known methods, in particular by gel permeation chromatography (GPC).

Without wishing to be bound by theory, the molecular weight of themonomer/comonomer may affect the material's vapor pressure andevaporation characteristics. For example, a monomer with a relativelylow molecular weight may exhibit too high a vapor pressure.Correspondingly, a monomer with a relatively high molecular weight mightbe unable to be evaporated. However, it should be appreciated thatvarying molecular weights may be suitable depending on the particularprocess used to form the polymer, the desired material properties of theresulting layer, and/or other factors.

Having generally described the types of polymers in the compositionsdescribed herein, the incorporation of the polymers into anelectrochemical cell will now be described. While many embodimentsdescribed herein describe lithium rechargeable electrochemical cells,any appropriate electrochemical cell chemistry could be used. Forexample, the description provided herein may refer to lithium/sulfurbatteries, other lithium metal batteries, or lithium ion batteries.Moreover, wherever lithium electrochemical cells are described herein,it is to be understood that any analogous alkali metal electrochemicalcells (including alkali metal anodes) can be used. Additionally,although rechargeable electrochemical cells are primarily disclosedherein, non-rechargeable (primary) electrochemical cells are intended tobenefit from the polymer embodiments described herein as well.

As described herein, in some embodiments an article such as an electrodeor electrochemical cell includes a protective structure thatincorporates one or more of the herein disclosed polymers to separate anelectroactive material from an electrolyte to be used with the electrodeor electrochemical cell. The separation of an electroactive layer fromthe electrolyte of an electrochemical cell can be desirable for avariety of reasons, including (e.g., for lithium batteries) theprevention of dendrite formation during recharging, preventing reactionof lithium with the electrolyte or components in the electrolyte (e.g.,solvents, salts and cathode discharge products), increasing cycle life,and improving safety (e.g., preventing thermal runaway). Reaction of anelectroactive lithium layer with the electrolyte may result in theformation of resistive film barriers on the anode, which can increasethe internal resistance of the battery and lower the amount of currentcapable of being supplied by the battery at the rated voltage.

While a variety of techniques and components for protection of lithiumand other alkali metal anodes are known, these protective coatingspresent particular challenges, especially in rechargeable batteries.Since lithium batteries function by removal and re-plating of lithiumfrom a lithium anode in each charge/discharge cycle, lithium ions mustbe able to pass through any protective coating. The coating must also beable to withstand morphological changes as material is removed andre-plated at the anode. The effectiveness of the protective structure inprotecting an electroactive layer may also depend, at least in part, onhow well the protective structure is integrated with the electroactivelayer, the presence of any defects in the structure, and/or thesmoothness of the layer(s) of the protective structure. Many single thinfilm materials, when deposited on the surface of an electroactivelithium layer, do not have all of the necessary properties of passing Liions, forcing a substantial amount of the Li surface to participate incurrent conduction, protecting the metallic Li anode against certainspecies (e.g., liquid electrolyte and/or polysulfides generated from asulfur-based cathode) migrating from the cathode, and impeding highcurrent density-induced surface damage.

The inventors of the present application have developed solutions toaddress the problems described herein through several embodiments of theinvention, including, in one set of embodiments, the combination of anelectroactive layer and a protective structure including a layer formedat least in part of a polymer described herein. In another set ofembodiments, an electroactive layer may include a protective structurein combination with a polymer gel layer formed from one or more thepolymers disclosed herein positioned adjacent the protective structure.

In another set of embodiments, solutions to the problems describedherein involve the use of an article including an anode comprisinglithium, or any other appropriate electroactive material, and amulti-layered structure positioned between the anode and an electrolyteof the cell. The multi-layered structure may serve as a protective layeror structure as described herein. In some embodiments, the multi-layeredstructure may include at least a first ion conductive material layer andat least a first polymeric layer formed from one or more of the polymersdisclosed herein and positioned adjacent the ion conductive material. Inthis embodiment, the multi-layered structure can optionally includeseveral sets of alternating ion conductive material layers and polymericlayers. The multi-layered structures can allow passage of lithium ions,while limiting passage of certain chemical species that may adverselyaffect the anode (e.g., species in the electrolyte). This arrangementcan provide significant advantage, as polymers can be selected thatimpart flexibility to the system where it can be needed most, namely, atthe surface of the electrode where morphological changes occur uponcharge and discharge.

In another embodiment, one or more of the polymers described herein maybe deposited between the active surface of an electroactive material andan electrolyte to be used in the electrochemical cell. Otherconfigurations of polymers and polymer layers are also provided herein.

Turning now to the figures, FIG. 1 shows a specific example of anarticle that can be used in an electrochemical cell according to one setof embodiments. As shown in this exemplary embodiment, article 10includes an anode 15 comprising an electroactive layer 20. Theelectroactive layer comprises an electroactive material (e.g., lithiummetal). In certain embodiments, the electroactive layer may covered by aprotective structure 30, which can include, for example, an ionconductive layer 30 a disposed on an active surface 20′ of theelectroactive layer 20 and a layer 30 b formed from one or more polymersdisclosed herein and disposed on the ion conductive layer 30 a. Theprotective structure may, in some embodiments, act as an effectivebarrier to protect the electroactive material from reaction with certainspecies in the electrolyte. In some embodiments, article 10 includes anelectrolyte 40, which may be positioned adjacent the protectivestructure, e.g., on a side opposite the electroactive layer. Theelectrolyte can function as a medium for the storage and transport ofions. In some instances, electrolyte 40 may comprise a gel polymerelectrolyte formed from the compositions disclosed herein.

A layer referred to as being “covered by”, “on”, or “adjacent” anotherlayer means that it can be directly covered by, on, or adjacent thelayer, or an intervening layer may also be present. A layer that is“directly adjacent”, “directly on”, or “in contact with”, another layermeans that no intervening layer is present. It should also be understoodthat when a layer is referred to as being “covered by”, “on”, or“adjacent” another layer, it may be covered by, on or adjacent theentire layer or a part of the layer.

It should be appreciated that FIG. 1 is an exemplary illustration andthat in some embodiments, not all components shown in the figure need bepresent. In yet other embodiments, additional components not shown inthe figure may be present in the articles described herein. For example,in some cases, protective structure 30 may be a multilayer structureincluding 3, 4, 5, or more layers, as described in more detail below. Inanother example, although FIG. 1 shows an ion conductive layer 30 adisposed on the surface of the electroactive layer, in otherembodiments, layer 30 b may be disposed on the surface of theelectroactive layer. Other configurations are also possible.

As noted above, in some embodiments, layer 30 b may formed from one ormore monomers having one or more electron withdrawing groups and/orelectron donating groups. In some embodiments, the monomer may be anolefinic monomer, acrylic monomer, styrenic monomer, vinylic monomer, orany other appropriate monomer. An olefinic monomer may comprise, in someinstances, at least one electron withdrawing group attached to a doublebond or at least one electron donating group attached to a double bond.In some embodiments, at least one of the olefinic monomers comprises atleast two double bonds, wherein each double bond has attached theretoone or more electron donating groups or one or more electron withdrawinggroups. The monomer may be able to participate in a free radicalmechanism to form a polymer. In certain embodiments, the monomerincludes an olefin positioned at one or more terminal ends of themonomer. In other embodiments, a monomer may include other reactivegroups suitable for polymerization including, but not limited to, alkynlgroups, dienes, thiols, epoxies, and other heroalkyl groups.

In some instances, the monomer is bifunctional, trifunctional, ormultifunctional. Without wishing to be bound by theory, branched and“multi-arm” structures may be considered to be multifunctional. Forexample, ethanol is monofunctional, glycol is bifunctional, glycerol istrifunctional, and pentaerythrol is tetrafunctional. Other non-limitingexamples of bifunctional monomers include, but are not limited to,triethyleneglcyol divinyl ether, 1,4-cyclohexanedimethanoldivinylether,1,4-Butanediol divinyl ether,1,1′-(Methylenedi-4,1-phenylene)bismaleimide, andN,N′-(1,4-Phenylene)dimaleimide.

As described herein, in some embodiments, a monomer or resulting polymer(e.g., a structural unit of a polymer) includes at least one electronwithdrawing group. An electron withdrawing group, in the context ofmonomers as described herein, generally refers to a group that drawselectrons away from the reaction center of the monomer, or away from thebackbone of the polymer. For example, the fluorine atom in the monomerHC═CHF is an electron withdrawing group with respect to the reactiveolefin group. When such a monomer is used to form into a polymer, thefluorine group is electron withdrawing with respect to the backbone ofthe polymer. The electron withdrawing groups described herein may havedifferent polarizations and reactivities, as described in more detailbelow. An electron withdrawing group may be charged or uncharged.

With regards to the polymer compositions, in one embodiment, the atleast one electron withdrawing group included in a monomer or resultingpolymer may be selected from a number of different compounds. Forexample, the monomer comprising at least one electron withdrawing groupmay be a functionalized olefin, a maleimide having the general structure

a (bis)maleimide having the general structure

or a maleic anhydride having the general structure

In other embodiments, an electron withdrawing group incorporated intothe monomer or resulting polymer (e.g., a repeat or structural unit of apolymer) may include, but is not limited to, a haloalkyl, —CN, —COOR₁,—C(═O)R₁, —CON(R₁)₂, —CONR₁H, halogen, —NO₂, —SO₃R₁, —SO(OR₁)₂,—SO(OR₁)H, —SOR₁, —SO₂R₁, —PO(OR₁)₂, —PO(OR1)H, and protonated aminegroups such as —NR3⁺ and —NH₃ ⁺, and —CF₃. In some embodiments involvingan olefinic monomer comprising at least one electron withdrawing groupattached to a double bond, two electron withdrawing groups attached inthe 1,2-position to the double bond may form together with the doublebond of a 5- to 6-membered substituted or unsubstituted, unsaturatedcycle or heterocycle. In other embodiments, a maleimide structure isused in which the phenyl/aryl is not the withdrawing group but both thecarbonyl groups attached to the olefinic group are electron withdrawing.In such an embodiment, the withdrawing effect may be enhanced by usingspecific moieties such as perfluorinated aryl, sulfonated aryl, or otherappropriate moieties.

Without wishing to be bound by theory, each of the above groups (e.g.,including a functionalized olefin, a maleimide, a (bis)maleimide, amaleic anhydride, and/or other electron withdrawing groups describedherein) may exhibit electron withdrawing properties regardless of thespecific functionality of R₁. Further, R₁ may exhibit electronwithdrawing or donating properties, or in some instances it may beneither electron withdrawing or donating. In some embodiments, R₁ mayexhibit functionalities that provide conductivity to the resultingpolymer. In the above compounds, each occurrence of R₁ may beindependently selected from hydrogen; halogen; substituted orunsubstituted, branched or unbranched aliphatic (e.g., an alkyl,alkenyl, alkynyl); substituted or unsubstituted cyclic (e.g.,cycloalkyl, cycloalkenyl, or cycloalkynyl); substituted orunsubstituted, branched or unbranched acyclic; substituted orunsubstituted, branched or unbranched heteroaliphatic; substituted orunsubstituted, branched or unbranched acyl; substituted or unsubstitutedaryl; substituted or unsubstituted heteroaryl; substituted orunsubstituted, branched or unbranched alkyelene oxide or poly(alkyleneoxide) such as substituted or unsubstituted, branched or unbranchedethylene oxide and substituted or unsubstituted, branched or unbranchedpropylene oxide; a metal ion; an anionic group; a lithium-containinggroup or a conducting salt such as a lithium-containing conducting salt(e.g., —SO₂NLiSO₂CF₃, aryl-SO₃Li (e.g., -PhSO₃Li) or alkyl-SO₃Li);and/or appropriate mixtures of the above. In certain embodiments,—CH₂CH₂O— may be included to provide conductivity to the resultingpolymer. In some embodiments, R₁ may be linked to at least one furtherelectron donating or electron withdrawing group attached to an olefinicdouble bond.

In embodiments in which the electron withdrawing group comprises aheteroaryl group, the heteroaryl group may be, for example, a 3-, 4-,5-, or 6-membered ring. In some embodiments, the heteroaryl groupcomprises one or more (e.g., 2, 3) heteroatoms in the ring of theheteroaryl structure. The one or more heteroatoms may each be, forexample, nitrogen, oxygen, sulfur, or phosphorus.

Several non-limiting examples of olefinic monomers incorporatingelectron withdrawing groups are depicted below.

Specific non-limiting examples of the functionalized maleimides aredepicted below. In addition to the use of maleimides, the monomer mayinclude (bis)maleimides. In the depicted embodiments, X may besubstituted or unsubstituted, branched or unbranched aliphatic (e.g., analkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, or cycloalkynyl);substituted or unsubstituted cyclic; substituted or unsubstituted,branched or unbranched acyclic; substituted or unsubstituted, branchedor unbranched heteroaliphatic; substituted or unsubstituted, branched orunbranched acyl; substituted or unsubstituted aryl; or substituted orunsubstituted heteroaryl, oxygen, or sulfur. In some cases, X is asubstituted or unsubstituted, branched or unbranched alkyelene oxide orpoly(alkylene oxide) such as substituted or unsubstituted, branched orunbranched ethylene oxide and substituted or unsubstituted, branched orunbranched propylene oxide; a metal ion; an anionic group; alithium-containing group or a conducting salt such as alithium-containing conducting salt (e.g., —SO₂NLiSO₂CF₃, aryl-SO₃Li(e.g., -PhSO₃Li) or alkyl-SO₃Li); and/or appropriate mixtures of theabove.

As described herein, in some embodiments, a monomer or resulting polymer(e.g., a structural unit of a polymer) includes at least one electrondonating group. An electron donating group, in the context of monomersand polymers as described herein, generally refers to a group thatdonates electrons towards the reaction center of the monomer, or towardsthe backbone of the polymer. For example, the —OCH₃ group in the monomerHC═CHOCH₃ is an electron donating group with respect to the reactiveolefin group. When such a monomer is used to form a polymer, the —OCH₃group is electron donating with respect to the backbone of the polymer.The electron donating groups described herein may have differentpolarizations and reactivities, as described in more detail below. Anelectron donating group may be charged or uncharged.

In some embodiments, the electron donating group included in a monomer(e.g., a comonomer) may be a functionalized olefin. In certainembodiments, an electron donating group incorporated into the monomer orresulting polymer (e.g., a structural unit of a polymer) may include,for example, at least one of an alkylamino, a heteroaryl, a cycloalkyl,a cycloalkenyl, a cycloalkynyl, —OCOR₂, —NR₂COR₂, —OR₂, —SR₂, —Si(OR₂)₃,—Si(OR₂)₂H, —Si(OR₂)H₂, —Si(R₂)₃, —Si(R₂)₂H, —Si(R₂)H₂,

In the above compounds each occurrence of R₂ may be selected fromhydrogen; substituted or unsubstituted, branched or unbranchedaliphatic; substituted or unsubstituted cyclic; substituted orunsubstituted, branched or unbranched acyclic; substituted orunsubstituted, branched or unbranched heteroaliphatic; substituted orunsubstituted, branched or unbranched acyl; substituted or unsubstitutedaryl; substituted or unsubstituted heteroaryl; substituted orunsubstituted, branched or unbranched alkyelene oxide or poly(alkyleneoxide) such as substituted or unsubstituted, branched or unbranchedethylene oxide, substituted or unsubstituted, branched or unbranchedpropylene oxide, polyethylene glycol, polypropylene glycol, and ethyleneoxide/propylene oxide mixtures; a metal ion; an anionic group; alithium-containing group or a conducting salt such as alithium-containing conducting salt (e.g., Aryl-SO₃Li (e.g., -PhSO₃Li),Alkyl-SO₃Li, and —SO₂NLiSO₂CF₃); and/or appropriate mixtures of theabove. In some of the above compounds, n is 1, 2 or 3. In certainembodiments, —CH₂CH₂O— may be included to provide conductivity to theresulting polymer. In some embodiments, R₂ may be optionally linked toat least one further electron donating or electron withdrawing groupattached to an olefinic double bond.

In embodiments in which the electron donating group comprises aheteroaryl group, the heteroaryl group may be, for example, a 3-, 4-,5-, or 6-membered ring. In some embodiments, the heteroaryl groupcomprises one or more (e.g., 2, 3) heteroatoms in the ring of theheteroaryl structure. The one or more heteroatoms may each be, forexample, nitrogen, oxygen, sulfur, or phosphorus.

In certain embodiments, the monomer including an electron donating groupmay comprise an ether group. In some embodiments, the ether group may bea polyether group (e.g., a polyalkylenoxide such as polyethyleneglycol). For example, the polyethylene glycol unit may be defined by theformula —(C₂H₄O)_(n)—, where n is an integer greater than 1. In someembodiments, n may be greater than or equal to 2, greater than or equalto 3, greater than or equal to 4, greater than or equal to 6, greaterthan or equal to 8, greater than or equal to 10, greater than or equalto 20, greater than or equal to 30, greater than or equal to 40, or anyother suitable value. In certain embodiments, n may be less than orequal to 50, less than or equal to 40, less than or equal to 30, lessthan or equal to 20, less than or equal to 10, less than or equal to 8,less than or equal to 6, less than or equal to 4, or less than or equalto 2, or any other suitable value. Combinations of the above-notedranges are also possible (e.g., n may be greater than or equal to 1 andless than or equal to 50). Other ranges of n are also possible.

In addition to the above, in one set of embodiments, at least one of themonomer and comonomer includes at least one functional group selectedfrom the group consisting of poly(ethylene oxide), poly(propyleneoxide), ethylene oxide/propylene oxide mixtures, lithiated sulfonategroups, lithiated carboxylate groups, and lithiatedtrifluoromethanesulfonylimide groups. In one particular embodiment, atleast one of the monomer and comonomer comprise poly(ethylene oxide).

In some cases, the monomer may be a vinyl ether. Non-limiting examplesof vinyl ethers include polyethylene glycol vinyl ethers, polyethyleneglycol divinyl ethers, triethylenglycol divinyl ether,tetraethyleneglycol divinyl ether, butandiol divinyl ether, dodecylvinyl ether, and cyclohexyl vinyl ether.

Several non-limiting examples of monomers (e.g., comonomers)incorporating electron donating groups are depicted below.

While some of the above embodiments described herein involve thecopolymerization of a monomer incorporating an electron withdrawinggroup and a comonomer incorporating an electron donating group, in otherembodiments, the functionality of both the monomer and comonomer may becombined in a single hybrid monomer. In certain embodiments, theresulting polymer formed from the hybrid monomer also includes anelectron withdrawing group and an electron donating group. For example,a hybrid monomer composed of an olefin or other reactive group suitablefor polymerization may be functionalized with both a functional groupthat acts as an electron withdrawing group and a functional group thatacts as an electron donating group. In some embodiments, the monomer isan olefinic monomer having at least two double bonds, at least oneelectron withdrawing group attached to one of the double bonds, and atleast one electron donating group attached to another of the doublebonds. In one particular embodiment, the olefinic monomer having atleast two double bonds comprises at least one maleimide or maleicanhydride and at least one vinyl ether.

Consequently, in one embodiment, a layer is formed by depositing onto asurface (and then subsequently polymerizing) an olefinic monomer havingat least one electron withdrawing group and at least one electrondonating group. In addition, the hybrid monomer may include one or moreof each type of functional group. The specific functional groupsincluded in a hybrid monomer may be selected from the above disclosedfunctional groups for the separate monomer including an electronwithdrawing group and comonomer including the electron donating group.One non-limiting example of a hybrid monomer is depicted below whereinthe carboxyl groups of the maleimide acts as electron withdrawing groupsand the polyethylene glycol group acts as an electron donating group:

In some embodiments involving the above-noted compound, n is an integergreater than 1. For example, n may be greater than or equal to 2,greater than or equal to 3, greater than or equal to 4, greater than orequal to 6, greater than or equal to 8, greater than or equal to 10,greater than or equal to 20, greater than or equal to 30, greater thanor equal to 40, or any other suitable value. In certain embodiments, nmay be less than or equal to 50, less than or equal to 40, less than orequal to 30, less than or equal to 20, less than or equal to 10, lessthan or equal to 8, less than or equal to 6, less than or equal to 4, orless than or equal to 2, or any other suitable value. Combinations ofthe above-noted ranges are also possible (e.g., n may be greater than orequal to 1 and less than or equal to 50). Other ranges of n are alsopossible.

As described herein, in one set of embodiments, the monomer including anelectron withdrawing group and the comonomer including an electrondonating group may be a maleimide (or maleic anhydride) and a vinylether, respectively. Specifically, the monomer including an electronwithdrawing group may be a monomer described herein, such as N-phenylmaleimide, a bismaleimide, a polyethylene oxide maleimide, or otherappropriate functionalized maleimide (or maleic anhydride). Thecomonomer including an electron donating group may be, for example, atriethylenglycol divinyl ether, butandiol divinyl ether, dodecyl vinylether, cyclohexyl vinyl ether, or other appropriate functionalized vinylether.

In certain embodiments in which the functionality of both the monomerand comonomer is combined in a single hybrid monomer, the resultingpolymer may be formed by polymerization of an olefinic monomer includingat least one maleimide or maleic anhydride and at least one vinyl ether.

In some embodiments, a polymer comprises a substituted or unsubstituted,branched or unbranched alkylene oxide or poly(alkylene oxide) (e.g.,ethylene oxide, poly(ethylene oxide), propylene oxide, or poly(propyleneoxide)), a metal ion; an anionic group; a lithium-containing group suchas a conducting salt (e.g., a lithium-containing conducting salt such as—SO₂NLiSO₂CF₃, aryl-SO₃Li (e.g., -PhSO₃Li) or alkyl-SO₃Li), and/orappropriate mixtures of the above.

As described herein, in certain embodiments, a monomer and/or polymerdescribed herein includes one or more lithium-containing groups, such asa lithium ion, e.g., in the form of a lithium salt. For example, R₁and/or R₂ may comprise a lithium ion (e.g., a lithium salt) and/or maybe conductive to lithium ions, in some embodiments. Such a monomerand/or polymer may be intrinsically conductive to lithium ions evenwithout the addition of dissolved lithium salts in a liquid electrolyte.In certain embodiments, such a monomer and/or polymer may be combinedwith one or more dissolved lithium salts in a liquid electrolyte toincrease ion conductivity. For example, such a monomer and/or polymermay be intrinsically ionically conductive by including one or morelithium salts (e.g., lithium-containing groups), and may be combinedwith one or more of the same lithium salts contained in the electrolyteto be used with the electrochemical cell.

In one embodiment, at least one of the monomers is bifunctional ormultifunctional (i.e., crosslinking). For example, vinyl ether whichmight be monofunctional (e.g., triethyleneglycol monomethyl vinyl ether)could be used with a bismaleimide. In another embodiment, both monomersare multifunctional. In yet another embodiment, both monomers aremonofunctional.

In some of the above referenced embodiments, the monomer and comonomerare polymerized in a one to one molar ratio. If desired, polymerizationin a ratio other than one to one may be possible. For example, the ratioof monomer including an electron withdrawing group to comonomer havingan electron donating group (e.g., in a reaction mixture and/or in theresulting polymer) may be, for example, greater than or equal to 0.1:1,greater than or equal to 0.2:1, greater than or equal to 0.5:1, greaterthan or equal to 0.7:1, greater than or equal to 1:1, greater than orequal to 1.5:1, greater than or equal to 2:1, greater than or equal to3:1, greater than or equal to 5:1, greater than or equal to 10:1. Insome cases, the ratio of monomer including an electron withdrawing groupto comonomer having an electron donating group (e.g., in a reactionmixture and/or in the resulting polymer) may be, for example, less thanor equal to 10:1, less than or equal to 5:1, less than or equal to 3:1,less than or equal to 2:1, less than or equal to 1.5:1, less than orequal to 1:1, less than or equal to 0.7:1, less than or equal to 0.5:1,less than or equal to 0.2:1, less than or equal to 0.1:1. Combinationsof the above-noted ranges are also possible (e.g., a ratio of greaterthan or equal to 0.1:1 and less than or equal to 1:1). Other ranges arealso possible. As an example, in some embodiments, excess vinyl ether(an electron donating group) may be supplied to act as a plasticizer forthe final co-polymerized material. Consequently, the structural and ionconductive properties of the resulting copolymer may be tailored byselecting the ratio of supplied monomer and comonomer.

In some of the above referenced embodiments, the molar ratio of doublebonds attached to an electron withdrawing group to double bonds attachedto an electron donating group is approximately one to one. If desired, amolar ratio other than one to one may be possible. For example, themolar ratio of double bonds attached to an electron withdrawing group todouble bonds attached to an electron donating group (e.g., in a reactionmixture) may be, for example, greater than or equal to 0.1:1, greaterthan or equal to 0.2:1, greater than or equal to 0.5:1, greater than orequal to 0.7:1, greater than or equal to 1:1, greater than or equal to1.5:1, greater than or equal to 2:1, greater than or equal to 3:1,greater than or equal to 5:1, greater than or equal to 10:1. In somecases, the molar ratio of double bonds attached to an electronwithdrawing group to double bonds attached to an electron donating group(e.g., in a reaction mixture) may be, for example, less than or equal to10:1, less than or equal to 5:1, less than or equal to 3:1, less than orequal to 2:1, less than or equal to 1.5:1, less than or equal to 1:1,less than or equal to 0.7:1, less than or equal to 0.5:1, less than orequal to 0.2:1, less than or equal to 0.1:1. Combinations of theabove-noted ranges are also possible (e.g., a ratio of greater than orequal to 0.1:1 and less than or equal to 1:1). Other ranges are alsopossible.

It should be appreciated that while the above-noted ranges describeratios of monomer including an electron withdrawing group to comonomerhaving an electron donating group, in embodiments in which more than twotypes of monomers are present (e.g., more than one monomer including anelectron withdrawing group and/or more than one comonomer having anelectron donating group), different ratios between different monomersmay be present. For example, the reaction mixture and/or resultingpolymer may have a ratio between a first monomer including an electronwithdrawing group to comonomer having an electron donating group thatfalls within a first range, such as one described above, and thereaction mixture and/or resulting polymer may have a ratio between asecond monomer including an electron withdrawing group to the comonomerhaving the electron donating group that falls within a second range,such as one described above. The first and second ranges may be the sameor different.

As described herein, it may be desirable to determine if a polymerformed from a specific monomer/comonomer has advantageous properties ascompared to other materials for particular electrochemical systems.Therefore, simple screening tests can be employed to help select betweencandidate materials. One simple screening test includes positioning alayer of the resulting polymer of the desired chemistry in anelectrochemical cell, e.g., as a separator in a cell. Theelectrochemical cell may then undergo multiple discharge/charge cycles,and the electrochemical cell may be observed for whether inhibitory orother destructive behavior occurs compared to that in a control system.If inhibitory or other destructive behavior is observed during cyclingof the cell, as compared to the control system, it may be indicative ofhydrolysis, or other possible degradation mechanisms of the polymer,within the assembled electrochemical cell. Using the sameelectrochemical cell it is also possible to evaluate the electricalconductivity and ion conductivity of the polymer using methods known toone of ordinary skill in the art. The measured values may be compared toselect between candidate materials and may be used for comparison withthe baseline material in the control.

Another simple screening test to determine if a polymer has suitablemechanical strength may be accomplished using any suitable mechanicaltesting methods including, but not limited to, durometer testing, yieldstrength testing using a tensile testing machine, and other appropriatetesting methods. In one set of embodiments, the polymer has a yieldstrength that is greater than or equal to the yield strength of metalliclithium. For example, the yield strength of the polymer may be greaterthan approximately 1 times, 2 times, 3 times, or 4 times the yieldstrength of metallic lithium. In some embodiments, the yield strength ofthe polymer is less than or equal to 10 times, 8 times, 6 times, 5times, 4 times, or 3 times the yield strength of metallic lithium.Combinations of the above-referenced ranges are also possible. In onespecific embodiment, the yield strength of the polymer is greater thanapproximately 10 kg/cm² (i.e., approximately 980 kPa). Other yieldstrengths greater than or less than the above limits are also possible.Other simple tests to characterize the polymers may also be conducted bythose of ordinary skill in the art.

Without wishing to be bound by theory, the strength of the resultingpolymer at various temperatures may be related to the glass transitiontemperature. Therefore, in some instances, the glass transitiontemperature of the polymer may be greater than or equal to approximately100° C., 110° C., 120° C., 130° C., 140° C., 150° C., or any otherappropriate temperature. Further, the glass transition temperature maybe less than or equal to approximately 200° C., 190° C., 180° C., 170°C., 160° C., or any other appropriate temperature. For example, theglass transition temperature may be between approximately 120° C. to200° C. or between approximately 150° C. to 180° C. Other combinationsof the above ranges are also possible. In some embodiments, the polymerdoes not exhibit a glass transition temperature.

A particular problem with lithium sulfur batteries is the thermalrunaway which can be observed at elevated temperatures between, e.g.,150 to 230° C. and which leads to complete destruction of the battery.Various methods have been suggested to prevent thermal runaway such asthe use of protective layers, including polymer coatings, for protectingthe electrodes. However, those methods usually lead to a dramaticreduction in capacity. The loss in capacity has been ascribed—amongstothers—to formation of lithium dendrites during recharging, loss ofsulfur due formation of soluble lithium sulfides such as Li₂S₃, Li₂S₄ orLi₂S₆, polysulfide shuttle, change of volume during charging ordischarging and others.

In some embodiments, the electrochemical cells described herein can becycled at relatively high temperatures without experiencing thermalrunaway. The term “thermal runaway” is understood by those of ordinaryskill in the art, and refers to a situation in which the electrochemicalcell cannot dissipate the heat generated during charge and dischargesufficiently fast to prevent uncontrolled temperature increases withinthe cell. Often, a positive feedback loop can be created during thermalrunaway (e.g., the electrochemical reaction produces heat, whichincreases the rate of the electrochemical reaction, which leads tofurther production of heat), which can cause electrochemical cells tocatch fire. In some embodiments, an electrochemical cell can include apolymer described herein (e.g., as part of a polymer layer, optionallyas a polymer electrolyte) such that thermal runaway is not observed atrelatively high temperatures of operation of the electrochemical cell.Not wishing to be bound by any particular theory, a polymer as describedherein may slow down the reaction between the lithium (e.g., metalliclithium) and the cathode active material (e.g., sulphur such aselemental sulfur) in the electrochemical cell, inhibiting (e.g.,preventing) thermal runaway from taking place. Also, the polymer mayserve as a physical barrier between the lithium and the cathode activematerial, inhibiting (e.g., preventing) thermal runaway from takingplace.

In some embodiments, the polymers described herein may aid in reducingor eliminating thermal runaway. This may be due to the fact that many ofthe polymers described herein are stable to high temperatures. In someembodiments, the polymers aid in operation of the electrochemical cell(e.g., continuously charged and discharged) at a temperature of up toabout 130° C., up to about 150° C., up to about 170° C., up to about190° C., up to 210° C., up to about 230° C., up to about 250° C., up toabout 270° C., up to about 290° C., up to about 300° C., up to about320° C., up to about 340° C., up to about 360° C., or up to about 370°C. (e.g., as measured at the external surface of the electrochemicalcell) without the electrochemical cell experiencing thermal runaway. Insome embodiments, the polymers described herein have a decompositiontemperature of greater than about 200° C., greater than about 250° C.,greater than about 300° C., or greater than about 350° C., or greaterthan about 370° C.

In some embodiments, the electrochemical cell can be operated at any ofthe temperatures outlined above without igniting. In some embodiments,the electrochemical cells described herein can be operated at relativelyhigh temperatures (e.g., any of the temperatures outlined above) withoutexperiencing thermal runaway (e.g., at ambient temperature and pressure)and without employing an auxiliary cooling mechanism (e.g., a heatexchanger external to the electrochemical cell, active fluid coolingexternal to the electrochemical cell, and the like).

The presence of thermal runaway in an electrochemical cell can beidentified by one of ordinary skill in the art. In some embodiments,thermal runaway can be identified by one or more of melted components,diffusion and/or intermixing between components or materials, thepresence of certain side products, and/or ignition of the cell.

Prior to copolymerization, the above-disclosed monomer and comonomer maybe deposited on a surface using any appropriate deposition technique.For example, a monomer may be deposited by methods such as electron beamevaporation, vacuum thermal evaporation, laser ablation, chemical vapordeposition, thermal evaporation, plasma assisted chemical vacuumdeposition, laser enhanced chemical vapor deposition, jet vapordeposition, and extrusion. The monomers may also be deposited byspin-coating, doctor blading, spray coating, and solution castingtechniques. Another method for depositing a monomer includes flashevaporation in which a monomer/comonomer solution is flash evaporated ina vacuum and subsequently condensed as a layer on a surface andpolymerized. U.S. Pat. No. 4,954,371 to Yializis describes the method inmore detail. Flash evaporation may also be used for deposition ofpolymer layers comprising salts, for example, as described in U.S. Pat.No. 5,681,615 to Affinito et al. The specific technique used fordepositing the monomer may depend on the material being deposited, thethickness of the desired layer, and other parameters as would beapparent to one of ordinary skill in the art. After deposition, thecopolymerization reaction may be initiated by UV light, electron beam,thermal energy, or any other appropriate energy source.

As described herein, in one particular embodiment, a method for forminga component for use in an electrochemical cell involves depositing ontoa surface at least one olefinic monomer comprising at least one electronwithdrawing group attached to a double bond and an at least one olefiniccomonomer comprising at least one electron donating group attached to adouble bond, and polymerizing the monomers using a free radicalmechanism to form a polymer layer. In certain embodiments, the olefinicmonomer comprising the at least one electron withdrawing group comprisesa maleimide or maleic anhydride and the comonomer comprising the atleast one electron donating group comprises a vinyl ether.

In embodiments where the one or more monomers are deposited onto asurface (e.g., a metallic surface or a ceramic/glass surface), it may bedesirable to include a third monomer (or second comonomer) (e.g., amonomer including an electron withdrawing group, an electron donatinggroup, or neither) having a functional group for tethering the resultingpolymer to the surface/substrate. In one embodiment, the molarpercentage of a third monomer with respect to a first monomer (e.g., amonomer including an electron withdrawing group), or molar percentage ofa third monomer with respect to a second monomer (e.g., a monomerincluding an electron donating group) in a reaction mixture (e.g., aliquid monomer film) may range from approximately 0.1 molar % toapproximately 20 molar %. For example, the percentage of a third monomerwith respect to a first monomer or a second monomer may be greater thanor equal to 0.1 molar %, greater than or equal to 1 molar %, greaterthan or equal to 5 molar %, greater than or equal to 10 molar %, orgreater than or equal to 15 molar %. In some embodiments, the molarpercentage of a third monomer with respect to a first monomer or asecond monomer may be less than or equal to 20 molar %, less than orequal to 15 molar %, less than or equal to 10 molar %, less than orequal to 5 molar %, or less than or equal to 1 molar %. Combinations ofthe above-noted ranges are also possible (e.g., greater than or equal to0.1 molar % and less than 5 molar %). Other ranges are also possible.

Several non-limiting examples of anchoring groups that can be includedin a third monomer for tethering the polymer to a metallic substrateinclude carboxylic acid, carboxylate, glycidyl groups, maleic anhydride,phosphonic acid ester, sulfonic acid, sulfonic acid esters, thiols,silanes, primary and secondary amino groups, ethoxylated ethers,siloxanes, and anionic groups. Although a third monomer comprising atethering group has been described, in other embodiments, one of themonomer having an electron withdrawing group and/or the comonomer havingan electron donating group may include a functional or anchoring groupsuch as one described above for tethering the resulting polymer to asubstrate.

In one particular set of embodiments, a polymer can be formed from thepolymerization of the following comonomers: an alkylene glycol divinylether (e.g., triethylene glycol divinyl ether), a maleic anhydride, anda maleimide (e.g., N-phenyl maleimide). A maleic anhydride may be usedto tether the resulting polymer to a substrate. A representative polymeris shown below.

In some embodiments, each of n and m may be, independently, greater thanor equal to approximately 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50,60, 70, or any other suitable value. Further, each of n and m may be,independently, less than or equal to approximately 100, 90, 80, 70, 60,50, 40, 30, 20, 10, 9, 8, 7, 6, 5, or any other suitable value. Forexample, each of n and m may be, independently, between approximately 1and 100 in some embodiments, or between approximately 1 and 10 in otherembodiments. Other combinations of the above-referenced ranges are alsopossible.

In some embodiments, the ratio of n:(m+o) is about 1:1. In someembodiments the ratio of n:(m+o) is greater than 1:1 (e.g., greater thanor equal to 1.5:1, greater than or equal to 2:1, greater than or equalto 3:1, greater than or equal to 5:1). In other embodiments, the ratioof n:(m+o) is less than 1:1 (e.g., less than or equal to 0.8:1, lessthan or equal to 0.6:1, less than or equal to 0.4:1, or less than orequal to 0.2:1). Other ranges are also possible.

In the polymer shown above, it should be appreciated that derivatives ofthe structural units denoted by n (e.g., the alkylene glycol divinylether), the structural units denoted by m (e.g., the maleimide), and/orthe structural units denoted by o (e.g., the maleic anhydride) may bepossible, and that the polymer need not include the specific structuralunits shown above. Additionally, it should be appreciated that incertain embodiments, the structural units denoted by n, and structuralunits denoted by either m or o, are alternating with respect to oneanother in the polymer chain.

In some embodiments, it may be beneficial to include a spacer groupbetween the monomer including the electron withdrawing group and thecomonomer including the electron donating group. Examples of possiblespacer groups include, but are not limited to, polyethylene oxide,polyethylene glycol, polypropylene oxide, and polybutylene oxide.Without wishing to be bound by theory, the inclusion of the above spacergroups may result in increased ionic conductivity and/or improvedflexibility of the resulting polymer. Additionally, benefits associatedspecifically with the inclusion of polyethylene glycol may include a lowtoxicity compared to other chemicals and/or a high viscosity which mayallow for the application of thin layers. In some embodiments, thespacer group is in the form of a polymer and includes a structural unit(e.g., repeat unit). In other embodiments, the spacer group does notinclude a structural unit (e.g., repeat unit). The spacer group may berandomly or non-randomly inserted between one or more types of monomersof the polymer.

While specific monomers and comonomers have been described above withregards to general classes of compounds, specific compounds, andassociated functional groups, it is also possible to describe themonomer and comonomer as being electron rich and electron poor partnerswhich may be polymerized, e.g., by a radical polymerization process. Onesuch way to describe the monomer and comonomer includes, but is notlimited to, Q-e scheme of the monomer and comonomer. Without wishing tobe bound by theory, the Q-e scheme is related to the polarizations andreactivities of the monomer and comonomer. For example, Q generallyrefers to the reactivity of a monomer/comonomer with higher values of Qindicating a more reactive monomer as compared to lower values of Q. evalues generally refer to the polarization of the monomer/comonomer withpositive values of e indicating an electron poor carbon double bond andnegative values indicating an electron rich carbon double bond. Withoutwishing to be bound by theory, in some embodiments, the e value is aconstant and the Q-e scheme can be applied more to the transition stateor the radical of the monomer rather than the monomer itself.

In one embodiment, the Q-e scheme of the monomer comprising the at leastone electron withdrawing group (e.g., at least one electron withdrawinggroup attached to a double bond) is e>0 and Q<0.1 and the Q-e scheme ofthe comonomer comprising the at least one electron donating group (e.g.,at least one electron donating group attached to a double bond) is e<0 aand Q>0.1. In another embodiment, the Q-e scheme of the monomercomprising the at least one electron withdrawing group (e.g., at leastone electron withdrawing group attached to a double bond) is e>0 andQ>0.1 and the Q-e scheme of the comonomer comprising the at least oneelectron donating group (e.g., at least one electron donating groupattached to a double bond) is e<0 a and Q<0.1. In some instances, the Qvalues of the monomer comprising the at least one electron withdrawinggroup and the comonomer comprising the at least one electron donatinggroup are approximately equal.

The term “aliphatic”, as used herein, includes both saturated andunsaturated, straight chain (i.e., unbranched), branched, acyclic,cyclic, or polycyclic aliphatic hydrocarbons, which are optionallysubstituted with one or more functional groups. As will be appreciatedby one of ordinary skill in the art, “aliphatic” is intended herein toinclude, but is not limited to, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, and cycloalkynyl moieties. Thus, as used herein, the term“alkyl” includes straight, branched and cyclic alkyl groups. Ananalogous convention applies to other generic terms such as “alkenyl”,“alkynyl”, and the like. Furthermore, as used herein, the terms “alkyl”,“alkenyl”, “alkynyl”, and the like encompass both substituted andunsubstituted groups. In certain embodiments, as used herein, “loweralkyl” is used to indicate those alkyl groups (cyclic, acyclic,substituted, unsubstituted, branched or unbranched) having 1-6 carbonatoms.

In certain embodiments, the alkyl, alkenyl, and alkynyl groups employedin the compounds described herein contain 1-20 aliphatic carbon atoms.For example, in some embodiments, an alkyl, alkenyl, or alkynyl groupmay have greater than or equal to 2 carbon atoms, greater than or equalto 4 carbon atoms, greater than or equal to 6 carbon atoms, greater thanor equal to 8 carbon atoms, greater than or equal to 10 carbon atoms,greater than or equal to 12 carbon atoms, greater than or equal to 14carbon atoms, greater than or equal to 16 carbon atoms, or greater thanor equal to 18 carbon atoms. In some embodiments, an alkyl, alkenyl, oralkynyl group may have less than or equal to 20 carbon atoms, less thanor equal to 18 carbon atoms, less than or equal to 16 carbon atoms, lessthan or equal to 14 carbon atoms, less than or equal to 12 carbon atoms,less than or equal to 10 carbon atoms, less than or equal to 8 carbonatoms, less than or equal to 6 carbon atoms, less than or equal to 4carbon atoms, or less than or equal to 2 carbon atoms. Combinations ofthe above-noted ranges are also possible (e.g., greater than or equal to2 carbon atoms and less than or equal to 6 carbon atoms). Other rangesare also possible.

Illustrative aliphatic groups include, but are not limited to, forexample, methyl, ethyl, n-propyl, isopropyl, cyclopropyl,—CH₂-cyclopropyl, vinyl, allyl, n-butyl, sec-butyl, isobutyl,tert-butyl, cyclobutyl, —CH₂-cyclobutyl, n-pentyl, sec-pentyl,isopentyl, tert-pentyl, cyclopentyl, —CH₂-cyclopentyl, n-hexyl,sec-hexyl, cyclohexyl, —CH₂-cyclohexyl moieties and the like, whichagain, may bear one or more substituents. Alkenyl groups include, butare not limited to, for example, ethenyl, propenyl, butenyl,1-methyl-2-buten-1-yl, and the like. Representative alkynyl groupsinclude, but are not limited to, ethynyl, 2-propynyl (propargyl),1-propynyl, and the like.

The term “alkoxy”, or “thioalkyl” as used herein refers to an alkylgroup, as previously defined, attached to the parent molecule through anoxygen atom or through a sulfur atom. In certain embodiments, the alkoxyor thioalkyl groups contain a range of carbon atoms, such as the rangesof carbon atoms described herein with respect to the alkyl, alkenyl, oralkynyl groups. Examples of alkoxy, include but are not limited to,methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, neopentoxy,and n-hexoxy. Examples of thioalkyl include, but are not limited to,methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, and thelike.

The term “alkylamino” refers to a group having the structure —NHR′,wherein R′ is aliphatic, as defined herein. In some cases, R′ may be R₁or R₂, as described herein. In certain embodiments, the alkylaminogroups contain a range of carbon atoms, such as the ranges of carbonatoms described herein with respect to the alkyl, alkenyl, or alkynylgroups. Examples of alkylamino groups include, but are not limited to,methylamino, ethylamino, n-propylamino, iso-propylamino,cyclopropylamino, n-butylamino, tert-butylamino, neopentylamino,n-pentylamino, hexylamino, cyclohexylamino, and the like.

The term “dialkylamino” refers to a group having the structure —NRR′,wherein R and R′ are each an aliphatic group, as defined herein. In somecases, R and R′ may be R₁ or R₂, as described herein. R and R′ may bethe same or different in an dialkyamino moiety. In certain embodiments,the dialkylamino groups contain a range of carbon atoms, such as theranges of carbon atoms described herein with respect to the alkyl,alkenyl, or alkynyl groups. Examples of dialkylamino groups include, butare not limited to, dimethylamino, methyl ethylamino, diethylamino,methylpropylamino, di(n-propyl)amino, di(iso-propyl)amino,di(cyclopropyl)amino, di(n-butyl)amino, di(tert-butyl)amino,di(neopentyl)amino, di(n-pentyl)amino, di(hexyl)amino,di(cyclohexyl)amino, and the like. In certain embodiments, R and R′ arelinked to form a cyclic structure. The resulting cyclic structure may bearomatic or non-aromatic. Examples of cyclic diaminoalkyl groupsinclude, but are not limited to, aziridinyl, pyrrolidinyl, piperidinyl,morpholinyl, pyrrolyl, imidazolyl, 1,3,4-trianolyl, and tetrazolyl.

Some examples of substituents of the above-described aliphatic (andother) moieties of compounds of the invention include, but are notlimited to aliphatic; heteroaliphatic; aryl; heteroaryl; arylalkyl;heteroarylalkyl; alkoxy; aryloxy; heteroalkoxy; heteroaryloxy;alkylthio; arylthio; heteroalkylthio; heteroarylthio; F; Cl; Br; I; —OH;—NO₂; —CN; —CF₃; —CH₂CF₃; —CHCl₂; —CH₂OH; —CH₂CH₂OH; —CH₂NH₂;—CH₂SO₂CH₃; —C(O)R_(x); —CO₂(R_(x)); —CON(R_(x))₂; —OC(O)R_(x);—OCO₂R_(x); —OCON(R_(x))₂; —N(R_(x))₂; —S(O)₂R_(x); —NR_(x)(CO)R_(x)wherein each occurrence of R_(x) independently includes, but is notlimited to, aliphatic, heteroaliphatic, aryl, heteroaryl, arylalkyl, orheteroarylalkyl, wherein any of the aliphatic, heteroaliphatic,arylalkyl, or heteroarylalkyl substituents described above and hereinmay be substituted or unsubstituted, branched or unbranched, cyclic oracyclic, and wherein any of the aryl or heteroaryl substituentsdescribed above and herein may be substituted or unsubstituted.Additional examples of generally applicable substituents are illustratedby the specific embodiments shown in the Examples that are describedherein.

In general, the terms “aryl” and “heteroaryl”, as used herein, refer tostable mono- or polycyclic, heterocyclic, polycyclic, andpolyheterocyclic unsaturated moieties having preferably 3-14 carbonatoms, each of which may be substituted or unsubstituted. Substituentsinclude, but are not limited to, any of the previously mentionedsubstituents, i.e., the substituents recited for aliphatic moieties, orfor other moieties as disclosed herein, resulting in the formation of astable compound. In certain embodiments described herein, “aryl” refersto a mono- or bicyclic carbocyclic ring system having one or twoaromatic rings including, but not limited to, phenyl, naphthyl,tetrahydronaphthyl, indanyl, indenyl, and the like. In certainembodiments, the term “heteroaryl”, as used herein, refers to a cyclicaromatic radical having from five to ten ring atoms of which one ringatom is selected from S, O, and N; zero, one, or two ring atoms areadditional heteroatoms independently selected from S, O, and N; and theremaining ring atoms are carbon, the radical being joined to the rest ofthe molecule via any of the ring atoms, such as, for example, pyridyl,pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl,oxazolyl, isooxazolyl, thiadiazolyl, oxadiazolyl, thiophenyl, furanyl,quinolinyl, isoquinolinyl, and the like.

It will be appreciated that aryl and heteroaryl groups can beunsubstituted or substituted, wherein substitution includes replacementof one, two, three, or more of the hydrogen atoms thereon independentlywith any one or more of the following moieties including, but notlimited to: aliphatic; heteroaliphatic; aryl; heteroaryl; arylalkyl;heteroarylalkyl; alkoxy; aryloxy; heteroalkoxy; heteroaryloxy;alkylthio; arylthio; heteroalkylthio; heteroarylthio; —F; —Cl; —Br; —I;—OH; —NO₂; —CN; —CF₃; —CH₂CF₃; —CHCl₂; —CH₂OH; —CH₂CH₂OH; —CH₂NH₂;—CH₂SO₂CH₃; —C(O)R_(x); —CO₂(R_(x)); —CON(R_(x))₂; —OC(O)R_(x);—OCO₂R_(x); —OCON(R_(x))₂; —N(R_(x))₂; —S(O)₂R_(x); —NR_(x)(CO)R_(x),wherein each occurrence of R_(x) independently includes, but is notlimited to, aliphatic, heteroaliphatic, aryl, heteroaryl, arylalkyl, orheteroarylalkyl, wherein any of the aliphatic, heteroaliphatic,arylalkyl, or heteroarylalkyl substituents described above and hereinmay be substituted or unsubstituted, branched or unbranched, cyclic oracyclic, and wherein any of the aryl or heteroaryl substituentsdescribed above and herein may be substituted or unsubstituted.Additional examples of generally applicable substituents are illustratedby the specific embodiments shown in the Examples that are describedherein.

The term “cycloalkyl”, as used herein, refers specifically to groupshaving three to seven, preferably three to ten carbon atoms. Suitablecycloalkyls include, but are not limited to cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl and the like, which, as in the caseof other aliphatic, heteroaliphatic, or heterocyclic moieties, mayoptionally be substituted with substituents including, but not limitedto aliphatic; heteroaliphatic; aryl; heteroaryl; arylalkyl;heteroarylalkyl; alkoxy; aryloxy; heteroalkoxy; heteroaryloxy;alkylthio; arylthio; heteroalkylthio; heteroarylthio; —F; —Cl; —Br; —I;—OH; —NO₂; —CN; —CF₃; —CH₂CF₃; —CHCl₂; —CH₂OH; —CH₂CH₂OH; —CH₂NH₂;—CH₂SO₂CH₃; —C(O)R_(x); —CO₂(R_(x)); —CON(R_(x))₂; —OC(O)R_(x);—OCO₂R_(x); —OCON(R_(x))₂; —N(R_(x))₂; —S(O)₂R_(x); —NR_(x)(CO)R_(x),wherein each occurrence of R_(x) independently includes, but is notlimited to, aliphatic, heteroaliphatic, aryl, heteroaryl, arylalkyl, orheteroarylalkyl, wherein any of the aliphatic, heteroaliphatic,arylalkyl, or heteroarylalkyl substituents described above and hereinmay be substituted or unsubstituted, branched or unbranched, cyclic oracyclic, and wherein any of the aryl or heteroaryl substituentsdescribed above and herein may be substituted or unsubstituted.Additional examples of generally applicable substituents are illustratedby the specific embodiments shown in the Examples that are describedherein.

The term “heteroaliphatic”, as used herein, refers to aliphatic moietiesthat contain one or more oxygen, sulfur, nitrogen, phosphorus, orsilicon atoms, e.g., in place of carbon atoms. Heteroaliphatic moietiesmay be branched, unbranched, cyclic or acyclic and include saturated andunsaturated heterocycles such as morpholino, pyrrolidinyl, etc. Incertain embodiments, heteroaliphatic moieties are substituted byindependent replacement of one or more of the hydrogen atoms thereonwith one or more moieties including, but not limited to aliphatic;heteroaliphatic; aryl; heteroaryl; arylalkyl; heteroarylalkyl; alkoxy;aryloxy; heteroalkoxy; heteroaryloxy; alkylthio; arylthio;heteroalkylthio; heteroarylthio; —F; —Cl; —Br; —I; —OH; —NO₂; —CN; —CF₃;—CH₂CF₃; —CHCl₂; —CH₂OH; —CH₂CH₂OH; —CH₂NH₂; —CH₂SO₂CH₃; —C(O)R_(x);—CO₂(R_(x)); —CON(R_(x))₂; —CC(O)R_(x); —OCO₂R_(x); —OCON(R_(x))₂;—N(R_(x))₂; —S(O)₂R_(x); —NR_(x)(CO)R_(x), wherein each occurrence ofR_(x) independently includes, but is not limited to, aliphatic,heteroaliphatic, aryl, heteroaryl, arylalkyl, or heteroarylalkyl,wherein any of the aliphatic, heteroaliphatic, arylalkyl, orheteroarylalkyl substituents described above and herein may besubstituted or unsubstituted, branched or unbranched, cyclic or acyclic,and wherein any of the aryl or heteroaryl substituents described aboveand herein may be substituted or unsubstituted. Additional examples ofgenerally applicable substituents are illustrated by the specificembodiments shown in the Examples that are described herein.

The terms “halo” and “halogen” as used herein refer to an atom selectedfrom fluorine, chlorine, bromine, and iodine.

The term “haloalkyl” denotes an alkyl group, as defined above, havingone, two, or three halogen atoms attached thereto and is exemplified bysuch groups as chloromethyl, bromoethyl, trifluoromethyl, and the like.

The term “heterocycloalkyl” or “heterocycle”, as used herein, refers toa non-aromatic 5-, 6-, or 7-membered ring or a polycyclic group,including, but not limited to a bi- or tri-cyclic group comprising fusedsix-membered rings having between one and three heteroatomsindependently selected from oxygen, sulfur and nitrogen, wherein (i)each 5-membered ring has 0 to 1 double bonds and each 6-membered ringhas 0 to 2 double bonds, (ii) the nitrogen and sulfur heteroatoms may beoptionally be oxidized, (iii) the nitrogen heteroatom may optionally bequaternized, and (iv) any of the above heterocyclic rings may be fusedto a benzene ring. Representative heterocycles include, but are notlimited to, pyrrolidinyl, pyrazolinyl, pyrazolidinyl, imidazolinyl,imidazolidinyl, piperidinyl, piperazinyl, oxazolidinyl, isoxazolidinyl,morpholinyl, thiazolidinyl, isothiazolidinyl, and tetrahydrofuryl. Incertain embodiments, a “substituted heterocycloalkyl or heterocycle”group is utilized and as used herein, refers to a heterocycloalkyl orheterocycle group, as defined above, substituted by the independentreplacement of one, two or three of the hydrogen atoms thereon with butare not limited to aliphatic; heteroaliphatic; aryl; heteroaryl;arylalkyl; heteroarylalkyl; alkoxy; aryloxy; heteroalkoxy;heteroaryloxy; alkylthio; arylthio; heteroalkylthio; heteroarylthio; —F;—Cl; —Br; —I; —OH; —NO₂; —CN; —CF₃; —CH₂CF₃; —CHCl₂; —CH₂OH; —CH₂CH₂OH;—CH₂NH₂; —CH₂SO₂CH₃; —C(O)R_(x); —CO₂(R_(x)); —CON(R_(x))₂; —OC(O)R_(x);—OCO₂R_(x); —OCON(R_(x))₂; —N(R_(x))₂; —S(O)₂R_(x); —NR_(x)(CO)R_(x),wherein each occurrence of R_(x) independently includes, but is notlimited to, aliphatic, heteroaliphatic, aryl, heteroaryl, arylalkyl, orheteroarylalkyl, wherein any of the aliphatic, heteroaliphatic,arylalkyl, or heteroarylalkyl substituents described above and hereinmay be substituted or unsubstituted, branched or unbranched, cyclic oracyclic, and wherein any of the aryl or heteroaryl substituentsdescribed above and herein may be substituted or unsubstituted.Additional examples of generally applicable substituents are illustratedby the specific embodiments shown in the Examples which are describedherein.

The term “independently selected” is used herein to indicate that the Rgroups can be identical or different.

The layer formed by or including a polymer composition described herein(e.g., a polymer layer) may have any suitable thickness. In someembodiments, the thickness may vary over a range from about 0.1 micronsto about 10 microns. For instance, the thickness of the layer may bebetween 0.05-0.15 microns thick, between 0.1-1 microns thick, between1-5 microns thick, or between 5-10 microns thick. The thickness of alayer may be, for example, less than or equal to 10 microns, less thanor equal to 5 microns, less than or equal to 2.5 microns, less than orequal to 1 micron, less than or equal to 500 nm, less than or equal to250 nm, less than or equal to 100 nm, less than or equal to 50 nm, lessthan or equal to 25 nm, or less than or equal to 10 nm. In certainembodiments, the layer may have a thickness of greater than 10 nm,greater than 25 nm, greater than 50 nm, greater than 100 nm, greaterthan 250 nm, greater than 500 nm, greater than 1 micron, greater than1.5 microns. Other thicknesses are also possible. Combinations of theabove-noted ranges are also possible (e.g., a thickness of greater than10 nm and less than or equal to 1 micron). The disclosed polymercompositions may be deposited using any of the above disclosed methods.

The dry state ion conductivity (i.e., the ion conductivity of thematerial when not swollen with an electrolyte) of the layer(s)comprising one or more polymers described herein may vary over a rangeof, for example, from about 10⁻⁸ S/cm to about 10⁻⁴ S/cm. In otherembodiments, the dry state ion conductivity may vary over a range fromabout 10⁻¹⁰ S/cm to about 10⁻⁴ S/cm. In some embodiments, the dry stateion conductivity may be, for example, less than or equal to 10⁻⁴ S/cm,less than or equal to 10⁻⁵ S/cm, less than or equal to 10⁻⁶ S/cm, orless than or equal to 10⁻⁷ S/cm. In certain embodiments, the dry stateion conductivity may be greater than or equal to 10⁻¹⁰ S/cm, 10⁻⁹ S/cm,10⁻⁸ S/cm, greater than or equal to 10⁻⁷ S/cm, greater than or equal to10⁻⁶ S/cm, or greater than or equal to 10⁻⁵ S/cm. Combinations of theabove-referenced ranges are also possible (e.g., a dry state ionconductivity of greater than or equal to 10⁻⁸ S/cm and less than orequal to 10⁻⁴ S/cm). Other dry state ion conductivities are alsopossible.

As shown in FIG. 1, in one set of embodiments, an article for use in anelectrochemical cell may include an ion-conductive layer. In someembodiments, the −ion conductive layer is a ceramic layer, a glassylayer, or a glassy-ceramic layer, e.g., an ion conducting ceramic/glassconductive to lithium ions. Suitable glasses and/or ceramics include,but are not limited to, those that may be characterized as containing a“modifier” portion and a “network” portion, as known in the art. Themodifier may include a metal oxide of the metal ion conductive in theglass or ceramic. The network portion may include a metal chalcogenidesuch as, for example, a metal oxide or sulfide. For lithium metal andother lithium-containing electrodes, an ion conductive layer may belithiated or contain lithium to allow passage of lithium ions across it.Ion conductive layers may include layers comprising a material such aslithium nitrides, lithium silicates, lithium borates, lithiumaluminates, lithium phosphates, lithium phosphorus oxynitrides, lithiumsilicosulfides, lithium germanosulfides, lithium oxides (e.g., Li₂O,LiO, LiO₂, LiRO₂, where R is a rare earth metal), lithium lanthanumoxides, lithium titanium oxides, lithium borosulfides, lithiumaluminosulfides, and lithium phosphosulfides, and combinations thereof.The selection of the ion conducting material will be dependent on anumber of factors including, but not limited to, the properties ofelectrolyte and cathode used in the cell.

In one set of embodiments, the ion conductive layer is anon-electroactive metal layer. The non-electroactive metal layer maycomprise a metal alloy layer, e.g., a lithiated metal layer especiallyin the case where a lithium anode is employed. The lithium content ofthe metal alloy layer may vary from about 0.5% by weight to about 20% byweight, depending, for example, on the specific choice of metal, thedesired lithium ion conductivity, and the desired flexibility of themetal alloy layer. Suitable metals for use in the ion conductivematerial include, but are not limited to, Al, Zn, Mg, Ag, Pb, Cd, Bi,Ga, In, Ge, Sb, As, and Sn. Sometimes, a combination of metals, such asthe ones listed above, may be used in an ion conductive material.

The thickness of a ion conductive material layer (e.g., within amulti-layered structure) may vary over a range from about 1 nm to about10 microns. For instance, the thickness of the ion conductive materiallayer may be between 1-10 nm thick, between 10-100 nm thick, between100-1000 nm thick, between 1-5 microns thick, or between 5-10 micronsthick. In some embodiments, the thickness of an ion conductive materiallayer may be, for example, less than or equal to 10 microns, less thanor equal to 5 microns, less than or equal to 1000 nm, less than or equalto 500 nm, less than or equal to 250 nm, less than or equal to 100 nm,less than or equal to 50 nm, less than or equal to 25 nm, or less thanor equal to 10 nm. In certain embodiments, the ion conductive layer mayhave a thickness of greater than or equal to 10 nm, greater than orequal to 25 nm, greater than or equal to 50 nm, greater than or equal to100 nm, greater than or equal to 250 nm, greater than or equal to 500nm, greater than or equal to 1000 nm, or greater than or equal to 1500nm. Combinations of the above-referenced ranges are also possible (e.g.,a thickness of greater than or equal to 10 nm and less than or equal to500 nm). Other thicknesses are also possible. In some cases, the ionconductive layer has the same thickness as a polymer layer in amulti-layered structure.

The ion conductive layer may be deposited by any suitable method such assputtering, electron beam evaporation, vacuum thermal evaporation, laserablation, chemical vapor deposition (CVD), thermal evaporation, plasmaenhanced chemical vacuum deposition (PECVD), laser enhanced chemicalvapor deposition, and jet vapor deposition. The technique used maydepend on the type of material being deposited, the thickness of thelayer, etc.

In some embodiments, the ion conductive material is non-polymeric. Incertain embodiments, the ion conductive material is defined in part orin whole by a layer that is highly conductive toward lithium ions (orother ions) and minimally conductive toward electrons. In other words,the ion conductive material may be one selected to allow certain ions,such as lithium ions, to pass across the layer, but to impede electrons,from passing across the layer. In some embodiments, the ion conductivematerial forms a layer that allows only a single ionic species to passacross the layer (i.e., the layer may be a single-ion conductive layer).In other embodiments, the ion conductive material may be substantiallyconductive to electrons.

In one set of embodiments, the ion conductive layer is a ceramic layer,a glassy layer, or a glassy-ceramic layer, e.g., an ion-conducting glassconductive to ions (e.g., lithium ions). For lithium metal and otherlithium-containing electrodes, an ion conductive layer may be lithiatedor contain lithium to allow passage of lithium ions across it. Ionconductive layers may include layers comprising a material such aslithium nitrides, lithium silicates, lithium borates, lithiumaluminates, lithium phosphates, lithium phosphorus oxynitrides, lithiumsilicosulfides, lithium germanosulfides, lithium oxides (e.g., Li₂O,LiO, LiO₂, LiRO₂, where R is a rare earth metal), lithium lanthanumoxides, lithium titanium oxides, lithium borosulfides, lithiumaluminosulfides, and lithium phosphosulfides, and combinations thereof.The selection of the ion conducting material will be dependent on anumber of factors including, but not limited to, the properties ofelectrolyte and cathode used in the cell.

The ion conductive layer may be formed using plasma conversion basedtechniques, electron beam evaporation, magnetron sputtering, chemicalvapor deposition, and any other appropriate formation technique,deposition technique, and/or any appropriate combination thereof.Alternatively, the layer of electroactive material may be exposed to agas, such as nitrogen, under suitable conditions to react with theelectroactive material at the surface of the electroactive materiallayer to form the ion conductive layer.

The noted conversion and/or deposition processes may be performed at anysuitable temperature and pressure. However, in some embodiments, theprocess is performed at a temperature less than the melting temperatureof the underlying substrate. In some embodiments, the temperature maybe, for example, less than 180° C., less than 150° C., less than 120°C., less than 100° C., less than 80° C., less than 60° C., or less than40° C. In certain embodiments, the temperature may be greater than 40°C., greater than 60° C., greater than 80° C., greater than 100° C.,greater than 120° C., or greater than 150° C. Other temperatures arealso possible. Combinations of the above-noted ranges are also possible.

The thickness of a ion conductive material layer may vary over a rangefrom about 1 nm to about 10 microns. For instance, the thickness of theion conductive material layer may be between 1-10 nm thick, between10-100 nm thick, between 100-1000 nm thick, between 1-5 microns thick,or between 5-10 microns thick. In some embodiments, the thickness of aion conductive material layer may be no greater than, e.g., 10 micronsthick, no greater than 5 microns thick, no greater than 1000 nm thick,no greater than 500 nm thick, no greater than 250 nm thick, no greaterthan 100 nm thick, no greater than 50 nm thick, no greater than 25 nmthick, or no greater than 10 nm thick. In certain embodiments, the ionconductive layer may have a thickness of greater than 10 nm, greaterthan 25 nm, greater than 50 nm, greater than 100 nm, greater than 250nm, greater than 500 nm, greater than 1000 nm, or greater than 1500 nm.Other thicknesses are also possible. Combinations of the above-notedranges are also possible. In some cases, the ion conductive layer hasthe same thickness as a polymer layer in a multi-layered structure.

The ion conductive layer may be deposited by any suitable method such assputtering, electron beam evaporation, vacuum thermal evaporation, laserablation, chemical vapor deposition (CVD), thermal evaporation, plasmaenhanced chemical vacuum deposition (PECVD), laser enhanced chemicalvapor deposition, and jet vapor deposition. The technique used maydepend on the type of material being deposited, the thickness of thelayer, etc.

In addition to the structures depicted in FIG. 1, the electrochemicalcell may include a structure including one or more layers comprising thedisclosed polymer and/or one or more layers of an ion conductivematerial positioned between the active surface of the electroactivematerial and the corresponding electrolyte of the cell. The one or morelayers comprising the polymer and/or one or more ion conductivematerials may form a multi-layered structure as described herein.

One advantage of a multi-layered structure includes the mechanicalproperties of the structure. The positioning of a polymer layer adjacentan ion conductive layer can decrease the tendency of the ion conductivelayer to crack, and can increase the barrier properties of thestructure. Thus, these laminates or composite structures may be morerobust towards stress due to handling during the manufacturing processthan structures without intervening polymer layers. In addition, amulti-layered structure can also have an increased tolerance of thevolumetric changes that accompany the migration of lithium back andforth from the anode during the cycles of discharge and charge of thecell.

One structure corresponding to such an embodiment is depicted in FIG.2A. In the depicted embodiment, article 10 includes an anode 15comprising an electroactive layer 20. The electroactive layer comprisesan electroactive material (e.g., lithium metal). In certain embodiments,the electroactive layer is covered by structure 30. As shown in theillustrative embodiment, structure 30 is disposed on the electroactivelayer 20 and is a multi-layered structure including at least a first ionconductive material layer 30 b and at least a first layer 30 a formedfrom or including one or more of the polymers disclosed herein andpositioned adjacent the ion conductive material. In this embodiment, themulti-layered structure can optionally include several sets ofalternating ion conductive material layers 30 a and layers 30 b. Themulti-layered structures can allow passage of, for example, lithiumions, while limiting passage of certain chemical species that mayadversely affect the anode (e.g., species in the electrolyte). Thisarrangement can provide significant advantage, as the polymers can beselected to impart flexibility to the system where it can be neededmost, namely, at the surface of the electrode where morphologicalchanges occur upon charge and discharge.

In other embodiments, as depicted in FIG. 2B, the electroactive layermay be covered by structure 30 formed from a single layer 30 b. Layer 30b may be formed from or comprise one or more of the polymers disclosedherein and may be disposed on active surface 20′ of the electroactivelayer.

A multi-layered structure may have various overall thicknesses that candepend on, for example, the electrolyte, the cathode, or the particularuse of the electrochemical cell. In some cases, a multi-layeredstructure can have an overall thickness less than or equal to 1 mm, lessthan or equal to 700 microns, less than or equal to 300 microns, lessthan or equal to 250 microns, less than or equal to 200 microns, lessthan or equal to 150 microns, less than or equal to 100 microns, lessthan or equal to 75 microns, less than or equal to 50 microns, less thanor equal to 20 microns, less than or equal to 10 microns, less than orequal to 5 microns, or less than or equal to 2 microns. In certainembodiments, the multi-layered structure may have a thickness of greaterthan 100 nm, greater than 250 nm, greater than 500 nm, greater than 1micron, greater than 2 microns, greater than 5 microns, greater than 10microns, or greater than 20 microns. Other thicknesses are alsopossible. Combinations of the above-noted ranges are also possible.

Examples of multi-layered structures are described in more detail inU.S. patent application Ser. No. 11/400,025, issued as U.S. Pat. No.7,771,870, and entitled “Electrode Protection in both Aqueous andNon-Aqueous Electrochemical Cells, including Rechargeable LithiumBatteries”, which is incorporated herein by reference in its entiretyfor all purposes.

As shown in the embodiment illustrated in FIG. 3, article 10 may beincorporated with other components to form an electrochemical cell 12.The electrochemical cell may optionally include a separator 50positioned adjacent or within the electrolyte. The electrochemical cellmay further include a cathode 60 comprising a cathode active material.Similar to above, a protective structure 30 may be incorporated betweenthe electroactive layer 20 and the electrolyte layer 40 and cathode 60.In the illustrative embodiment of FIG. 3, protective structure 30comprises a plurality of ion conductive layers 30 a and layers 30 b. Theion conductive layers 30 a and layers 30 b are arranged in analternating pattern. The layers 30 b may be formed from or may compriseone or more of the polymer compositions disclosed herein. While fourseparate layers have been depicted, it should be appreciated that anysuitable number of desired layers could be used (e.g., 5, 6, 7, 8separate layers).

In one set of embodiments, electroactive layer 20 includes lithium(e.g., lithium metal). However, the current disclosure is not limited tothe specific active materials disclosed herein. Instead, the currentdisclosure should be viewed broadly as disclosing protective structuresfor use in any number of electrochemical cells of varying chemistry.

In another set of embodiments, electrolyte layer 40, as shownillustratively in FIG. 3, may comprise a polymer gel formed from thepolymers disclosed herein. As known to those of ordinary skill in theart, when a solvent is added to a polymer and the polymer is swollen inthe solvent to form a gel, the polymer gel is more easily deformed (and,thus, has a lower yield strength) than the polymer absent the solvent.The yield strength of a particular polymer gel may depend on a varietyof factors such as the chemical composition of the polymer, themolecular weight of the polymer, the degree of crosslinking of thepolymer if any, the thickness of the polymer gel layer, the chemicalcomposition of the solvent used to swell the polymer, the amount ofsolvent in the polymer gel, any additives such as salts added to thepolymer gel, the concentration of any such additives, and the presenceof any cathode discharge products in the polymer gel.

In some embodiments, the polymer gel is formed by swelling at least aportion of the polymer in a solvent to form the gel. The polymers may beswollen in any appropriate solvent. The solvent may include, forexample, dimethylacetamide (DMAc), N-methylpyrolidone (NMP),dimethylsulfoxide (DMSO), dimethylformamide (DMF), sulfolanes, sulfones,and/or any other appropriate solvent. In certain embodiments, thepolymer may be swollen in a solvent mixture comprising a solvent havingaffinity to polymer and also solvents having no affinity to the polymer(so-called non-solvents) such as, for PVOH, 1,2.dimethoxyethane (DME),diglyme, triglyme, 1.3-dioxolane (DOL), THF, 1,4-dioxane, cyclic andlinear ethers, esters (carbonates such as dimethylcarbonate and ethylenecarbonate), acetals and ketals. The solvents for preparing the polymergel may be selected from the solvents described herein and may compriseelectrolyte salts, including lithium salts selected from the lithiumsalts described herein.

In some embodiments, a polymer layer (e.g., a protective polymer layeror a polymer gel layer) and/or an electrolyte may include one or moreionic electrolyte salts (e.g., dissolved ionic salts), also as known inthe art, to increase the ionic conductivity. Examples of ionicelectrolyte salts include, but are not limited to, LiTFSI, LiFSI, LiI,LiPF₆, LiAsF₆, LiBOB, derivatives thereof, and other appropriate salts.In some embodiments, the polymer layer comprises a polymer that includesa lithium-containing group such as a lithium salt (e.g., in one or moreof its R groups, such as R₁ and/or R₂), as described herein.

The gel state ion conductivity (i.e. the ion conductivity of thematerial when swollen with an electrolyte) of the polymer layers mayvary over a range from, for example, about 10⁻⁷ S/cm to about 10⁻³ S/cm.In some embodiments, the gel state ion conductivity may be, for example,less than or equal to 10⁻³ S/cm, less than or equal to 10⁻⁴ S/cm, lessthan or equal to 10⁻⁵ S/cm. In certain embodiments, the gel state ionconductivity may be greater than or equal to 10⁻⁷ S/cm, greater than orequal to 10⁻⁶ S/cm, greater than or equal to 10⁻⁵ S/cm, greater than orequal to 10⁻⁴ S/cm. Combinations of the above-referenced ranges are alsopossible (e.g., a gel state ion conductivity of greater than or equal togreater than or equal to 10⁻⁷ S/cm and less than or equal to 10⁻³ S/cm).Other gel state ion conductivities are also possible.

As shown illustratively in FIG. 3, an electrochemical cell or an articlefor use in an electrochemical cell may include a cathode active materiallayer. Suitable electroactive materials for use as cathode activematerials in the cathode of the electrochemical cells described hereinmay include, but are not limited to, electroactive transition metalchalcogenides, electroactive conductive polymers, sulfur, carbon and/orcombinations thereof. As used herein, the term “chalcogenides” pertainsto compounds that contain one or more of the elements of oxygen, sulfur,and selenium. Examples of suitable transition metal chalcogenidesinclude, but are not limited to, the electroactive oxides, sulfides, andselenides of transition metals selected from the group consisting of Mn,V, Cr, Ti, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re,Os, and Ir. In one embodiment, the transition metal chalcogenide isselected from the group consisting of the electroactive oxides ofnickel, manganese, cobalt, and vanadium, and the electroactive sulfidesof iron. In one embodiment, a cathode includes one or more of thefollowing materials: manganese dioxide, iodine, silver chromate, silveroxide and vanadium pentoxide, copper oxide, copper oxyphosphate, leadsulfide, copper sulfide, iron sulfide, lead bismuthate, bismuthtrioxide, cobalt dioxide, copper chloride, manganese dioxide, andcarbon. In another embodiment, the cathode active layer comprises anelectroactive conductive polymer. Examples of suitable electroactiveconductive polymers include, but are not limited to, electroactive andelectronically conductive polymers selected from the group consisting ofpolypyrroles, polyanilines, polyphenylenes, polythiophenes, andpolyacetylenes. Examples of conductive polymers include polypyrroles,polyanilines, and polyacetylenes.

In some embodiments, electroactive materials for use as cathode activematerials in electrochemical cells described herein includeelectroactive sulfur-containing materials. “Electroactivesulfur-containing materials,” as used herein, relates to cathode activematerials which comprise the element sulfur in any form, wherein theelectrochemical activity involves the oxidation or reduction of sulfuratoms or moieties. The nature of the electroactive sulfur-containingmaterials useful in the practice of this invention may vary widely, asknown in the art. For example, in one embodiment, the electroactivesulfur-containing material comprises elemental sulfur. In anotherembodiment, the electroactive sulfur-containing material comprises amixture of elemental sulfur and a sulfur-containing polymer. Thus,suitable electroactive sulfur-containing materials may include, but arenot limited to, elemental sulfur and organic materials comprising sulfuratoms and carbon atoms, which may or may not be polymeric. Suitableorganic materials include those further comprising heteroatoms,conductive polymer segments, composites, and conductive polymers.

Suitable electroactive materials for use as anode active materials inthe electrochemical cells described herein include, but are not limitedto, lithium metal such as lithium foil and lithium deposited onto aconductive substrate, and lithium alloys (e.g., lithium-aluminum alloysand lithium-tin alloys). While these are preferred materials, other cellchemistries are also contemplated. In some embodiments, the anode maycomprise one or more binder materials (e.g., polymers, etc.).

The articles described herein may further comprise a substrate, as isknown in the art. Substrates are useful as a support on which to depositthe anode active material, and may provide additional stability forhandling of thin lithium film anodes during cell fabrication. Further,in the case of conductive substrates, a substrate may also function as acurrent collector useful in efficiently collecting the electricalcurrent generated throughout the anode and in providing an efficientsurface for attachment of electrical contacts leading to an externalcircuit. A wide range of substrates are known in the art of anodes.Suitable substrates include, but are not limited to, those selected fromthe group consisting of metal foils, polymer films, metallized polymerfilms, electrically conductive polymer films, polymer films having anelectrically conductive coating, electrically conductive polymer filmshaving an electrically conductive metal coating, and polymer filmshaving conductive particles dispersed therein. In one embodiment, thesubstrate is a metallized polymer film. In other embodiments, describedmore fully below, the substrate may be selected fromnon-electrically-conductive materials.

The electrolytes used in electrochemical or battery cells can functionas a medium for the storage and transport of ions, and in the specialcase of solid electrolytes and gel electrolytes, these materials mayadditionally function as a separator between the anode and the cathode.Any liquid, solid, or gel material capable of storing and transportingions may be used, so long as the material facilitates the transport ofions (e.g., lithium ions) between the anode and the cathode. Theelectrolyte is electronically non-conductive to prevent short circuitingbetween the anode and the cathode. In some embodiments, the electrolytemay comprise a non-solid electrolyte.

In some embodiments, an electrolyte layer described herein may have athickness of at least 1 micron, at least 5 microns, at least 10 microns,at least 15 microns, at least 20 microns, at least 25 microns, at least30 microns, at least 40 microns, at least 50 microns, at least 70microns, at least 100 microns, at least 200 microns, at least 500microns, or at least 1 mm. In some embodiments, the thickness of theelectrolyte layer is less than or equal to 1 mm, less than or equal to500 microns, less than or equal to 200 microns, less than or equal to100 microns, less than or equal to 70 microns, less than or equal to 50microns, less than or equal to 40 microns, less than or equal to 30microns, less than or equal to 20 microns, less than or equal to 10microns, or less than or equal to 50 microns. Other values are alsopossible. Combinations of the above-noted ranges are also possible.

The electrolyte can comprise one or more ionic electrolyte salts toprovide ionic conductivity and one or more liquid electrolyte solvents,gel polymer materials, or polymer materials. Suitable non-aqueouselectrolytes may include organic electrolytes comprising one or morematerials selected from the group consisting of liquid electrolytes, gelpolymer electrolytes, and solid polymer electrolytes. Examples of usefulnon-aqueous liquid electrolyte solvents include, but are not limited to,non-aqueous organic solvents, such as, for example, N-methyl acetamide,acetonitrile, acetals, ketals, esters, carbonates, sulfones, sulfites,sulfolanes, aliphatic ethers, acyclic ethers, cyclic ethers, glymes,polyethers, phosphate esters, siloxanes, dioxolanes,N-alkylpyrrolidones, substituted forms of the foregoing, and blendsthereof. Examples of acyclic ethers that may be used include, but arenot limited to, diethyl ether, dipropyl ether, dibutyl ether,dimethoxymethane, trimethoxymethane, dimethoxyethane, diethoxyethane,1,2-dimethoxypropane, and 1,3-dimethoxypropane. Examples of cyclicethers that may be used include, but are not limited to,tetrahydrofuran, tetrahydropyran, 2-methyltetrahydrofuran, 1,4-dioxane,1,3-dioxolane, and trioxane. Examples of polyethers that may be usedinclude, but are not limited to, diethylene glycol dimethyl ether(diglyme), triethylene glycol dimethyl ether (triglyme), tetraethyleneglycol dimethyl ether (tetraglyme), higher glymes, ethylene glycoldivinyl ether, diethylene glycol divinyl ether, triethylene glycoldivinyl ether, dipropylene glycol dimethyl ether, and butylene glycolethers. Examples of sulfones that may be used include, but are notlimited to, sulfolane, 3-methyl sulfolane, and 3-sulfolene. Fluorinatedderivatives of the foregoing are also useful as liquid electrolytesolvents. Mixtures of the solvents described herein can also be used.

EXAMPLES Example 1

This example shows the polymerization of comonomers triethylene glycoldivinyl ether and N-phenyl maleimide. Testing was conducted to determinethe dry state conductivity and other properties of the resultingpolymer.

A solution of 20.23 g triethylene glycol divinyl ether and 17.32 gN-phenyl maleimide was dissolved in 38 g methyl ethyl ketone (MEK)together with 0.75 g Irgacure 819 and 2.63 g of the electrolytesolution. The electrolyte solution consisted of one part 1,3-dioxolane(DOL) and one part dimethoxyethane (DME) with 8-16% LiTFSI, 2-8% LiNO3,0-1% guanidinium nitrate and 0-0.4% pyridinium nitrate. The solution wascast on a polymer substrate via doctor blading for determination of drystate conductivities. The coated substrate was quickly transferred intoa belt conveyor where it was cured by UV light from a broad band mercurylamp which provided a dose of 2500 mJ/cm² over a duration ofapproximately 20 seconds. The polymer film was carefully dried in anoven under vacuum. The resulting film thicknesses prepared in this waywere in the range of 1-50 μm.

Electrochemical characterization was performed using a Hiresta-UP modelMCP-HT 450. The testing procedure involved using a four-point probe tomeasure the resistance, surface resistivity, and volume resistivity.From these measurements and the thickness of the film, dryconductivities were calculated. The measured dry state conductivityvaried from approximately 10⁻⁸ S/cm to as low as 10⁻¹² and 10⁻¹³ S/cm.Differential Scanning calorimetry revealed a relatively high glasstransition temperature of 160° C. The relatively high glass transitiontemperature delays the onset of plastic flow in the material at the sametemperatures as compared to other polymers with lower glasstemperatures. Since the disclosed material does not flow as easily atelevated temperatures it may provide increased protection from contactbetween opposing electrodes of an electrochemical cell during a thermalrunaway event. Thus, the polymers described herein may provide improvedsafety with regards to shorting of an electrochemical cell during athermal runaway event. Without wishing to be bound by theory, andelevated glass transition temperature may also impart improvedmechanical strength to the polymer and reduce movement of the materialswithin the battery when it is heated during manufacture and use.

Example 2

In a prophetic example, diethylene glycol divinyl ether andN-triethylene glycol maleimide comonomers may undergo a copolymerizationreaction. Without wishing to be bound by theory, it is expected that theconductivity of such a combination may be higher, as compared to thecurrently disclosed results of Example 1, due to higher amounts ofpolyethylene glycol units and relatively high flexibility of the chains.It is expected that dry state conductivities may be approximately 2-3orders of magnitude higher than the currently disclosed results ofExample 1, e.g., 10⁻⁶ S/cm up to 10⁻⁵ S/cm.

Example 3

This example shows the polymerization of comonomers triethylene glycoldivinyl ether and N-phenyl maleimide. Testing was conducted to determinethe gel state conductivity of the resulting polymer.

A solution of 20.23 g triethylene glycol divinyl ether and 17.32 gN-phenyl maleimide was dissolved in 38 g MEK together with 0.75 gIrgacure 819 and 2.63 g of the electrolyte solution. The electrolytesolution contained one part 1,3-dioxolane (DOL) and one partdimethoxyethane (DME) with 8-16% LiTFSI, 2-8% LiNO3, 0-1% guanidiniumnitrate and 0-0.4% pyridinium nitrate. The solution was cast onto acopper substrate via doctor blading for determination of gel stateconductivities. Other possible substrates include, but are not limitedto, lithium and nickel. The coated substrate was quickly transferredinto a belt conveyor where it was cured by UV light from a broad bandmercury lamp which provided a dose of 2500 mJ/cm² over a duration ofapproximately 20 seconds. The polymer film was carefully dried in anoven under vacuum at approximately 80° C. for approximately one hour toremove excess solvent and/or water. Alternatively, the polymer filmcould have been dried in a dry room at room temperature. The actualelectrochemical performance was evaluated in a pouch cell set-up. Oncethe cells were manufactured the pouch cells were filled with electrolyteand allowed to rest over night to allow for equilibration. The resultinggel state ionic conductivity of the resulting cell was determined to beon the order of 10⁻⁴ S/cm.

Example 4

In a prophetic example, a PEGylated maleimide monomer may be combinedwith a PEGylated vinyl ether. The combined monomer and comonomer maysubsequently undergo a copolymerization reaction. Without wishing to bebound by theory, it is believed that such a polymer may provide optimumconductivities of approximately 10⁻⁴ up to approximately 10⁻³. Thepolymer is expected to provide the above noted conductivities becauseexperiments with triethyleneglycol-divinylether (TEGDVE) includingacrylamide as a monofunctional monomer have given gel conductivities ashigh as 10⁻³ S/cm. Without wishing to be bound by theory, it wasobserved that the ethoxylate chain of the olefin provided the elevatedionic conductivity regardless of the specific monofunctional monomerutilized during testing. Additionally, the alkyl chain and maleimidemoiety allow for more ionic conductivity due to more flexible chainmovement resulting in higher movement of Li ions. Therefore, theelevated conductivities noted above are expected for the proposedcombination of a PEGylated maleimide monomer with a PEGylated vinylether. In addition to the above, the combination of PEGylated maleimideand PEGylated vinyl ether may also result in a beneficial balance ofmaterial stiffness versus ion conductivity.

Example 5

This example shows the polymerization of comonomers triethylene glycoldivinyl ether, maleic anhydride, and N-phenyl maleimide. The maleicanhydride was added to tether the resulting polymer to a substrate.

A solution of 10.12 g triethylene glycol divinyl ether, 0.30 g maleicanhydride, and 8.79 g N-phenyl maleimide was dissolved in 19 g MEKtogether with 0.37 g Irgacure 819 and 1.41 g of the electrolytesolution. Without wishing to be bound by theory, it is believed that themaleic anhydride may act as a tether to attach the resulting polymerfilm to an underlying metallic substrate. The electrolyte solutioncontained one part 1,3-dioxolane (DOL) and one part dimethoxyethane(DME) with 8-16% LiTFSI, 2-8% LiNO3, 0-1% guanidinium nitrate and 0-0.4%pyridinium nitrate. The solution was cast onto a nickel metal substratevia doctor blading for determination of gel state conductivities. Thecoated substrate was quickly transferred into a belt conveyor where itwas cured by UV light from a broad band mercury lamp which provided adose of 2500 mJ/cm² over a duration of approximately a 20 seconds. Thepolymer film was carefully dried in an oven under vacuum at 80° C. forone hour.

The actual electrochemical performance was evaluated in a pouch cellset-up. Once the cells were manufactured the electrolyte was filled intothe pouch cell. The cells rested over night to allow for equilibration.The resulting film was mechanically stable on metal substrates likenickel, i.e., it did not detach from the surface. By this approach itwas possible to realize a stable film on a nickel anode and successfullysuppress dewetting. The ionic conductivities in the gel state andtethered to an underlying substrate were in the range of 10⁻⁵ to 10⁻⁴S/cm.

Example 6

A solution of 0.85 g 1,4-cyclohexanedimethanoldivinylether, 1.46 gN-phenylmaleimide, 0.19 g LiTFSI, and 0.0231 g 1819 was dissolved in2.31 g DOL. The system was degassed using a vacuum pump before beingcoated on copper foil using a MR15. Utilizing a conveyor belt, thecoating was passed under the UV light of a broad spectrum mercury lampwith an exposure of 2.2-20.3 mJ/second. Coatings were allowed to dry for20-60 minutes at room temperature in a dry room. The sample wasevaluated for gel conductivity in the form of a small flat cell filledwith electrolyte composed of 8-16% LiTFSI, 2-8% LiNO₃, 0-1% guanidiniumnitrate and 0-0.4% pyridinium nitrate. The gel conductivity of thissample was 2.7×10⁻⁴ S/cm.

Example 7

A solution of 0.77-0.90 g triethylene glycol divinyl ether or1,4-cyclohexanedimethanoldivinylether, 1.54-1.46 g N-phenylmaleimide,0.19 g LiTFSI, and 0.0231 g 1819 was dissolved in 2.31 g dioxane. Thesystem was degassed using a vacuum pump before being coated on copperfoil using a MR15. Utilizing a conveyor belt, the coating was passedunder the UV light of a broad spectrum mercury lamp with an exposure of2.2-20.3 mJ/second. Coatings were allowed to dry for 20-60 minutes atroom temperature in a dry room. The sample was evaluated for gelconductivity in the form of a small flat cell filled with electrolytecomposed of 8-16% LiTFSI, 2-8% LiNO3, 0-1% guanidinium nitrate and0-0.4% pyridinium nitrate. The gel conductivity of these samples were onthe order of magnitude of 10⁻⁴ S/cm.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, kit, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,kits, and/or methods, if such features, systems, articles, materials,kits, and/or methods are not mutually inconsistent, is included withinthe scope of t and an the present invention.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Other elements may optionallybe present other than the elements specifically identified by the“and/or” clause, whether related or unrelated to those elementsspecifically identified unless clearly indicated to the contrary. Thus,as a non-limiting example, a reference to “A and/or B,” when used inconjunction with open-ended language such as “comprising” can refer, inone embodiment, to A without B (optionally including elements other thanB); in another embodiment, to B without A (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” and the like are to be understoodto be open-ended, i.e., to mean including but not limited to. Only thetransitional phrases “consisting of” and “consisting essentially of”shall be closed or semi-closed transitional phrases, respectively, asset forth in the United States Patent Office Manual of Patent ExaminingProcedures, Section 2111.03.

What is claimed is:
 1. A method for forming a component for use in anelectrochemical cell, the method comprising: providing an electroactivelayer; depositing onto a surface of the electroactive layer: a) anolefinic monomer comprising a maleimide which includes at least onedouble bond and at least one electron withdrawing group and at least oneolefinic comonomer, different than the olefinic monomer, comprising atleast one double bond and at least one electron donating group; or b) anolefinic monomer comprising a maleimide which includes at least onedouble bond and at least one electron withdrawing group, the olefinicmonomer further comprising at least one additional double bond and atleast one electron donating group, and at least one olefinic comonomer,different than the olefinic monomer; polymerizing the monomer(s) using afree radical mechanism to form a polymer; wherein the polymer includesstructural units comprising the at least one electron withdrawing groupthat alternate with structural units comprising the at least oneelectron donating group; wherein the electron withdrawing group isselected from the group consisting of CON(R₁)₂ and —CONR₁H; wherein twoelectron withdrawing groups attached in the 1,2-position to the doublebond may form together with the double bond of a 5- to 6-memberedsubstituted or unsubstituted, unsaturated cycle or heterocycle; whereinR₁ may be linked to at least one further electron donating or electronwithdrawing group; wherein each occurrence of R₁ is independentlyselected from the group consisting of hydrogen; halogen; substituted orunsubstituted, branched or unbranched acyl; substituted or unsubstitutedaryl; substituted or unsubstituted heteroaryl; a metal ion, and alithium-containing group; and wherein a gel state ion conductivity ofthe polymer is greater than or equal to 10⁻⁴ S/cm.
 2. A method as inclaim 1, wherein the comonomer comprising the at least one electrondonating group comprises a vinyl ether.
 3. A method as in claim 1,wherein depositing the olefinic monomer and the olefinic comonomer ofa), or depositing the olefinic monomer of b), comprises using at leastone of doctor blading, spray coating, spin coating, solution casting,and vapor deposition.
 4. A method as in claim 1, wherein depositing theolefinic monomer and the olefinic comonomer of a), or depositing theolefinic monomer of b), comprises using flash evaporation.
 5. A methodas in claim 1, wherein polymerizing comprises applying at least one ofUV light, an electron beam, or thermal energy to the olefinic monomerand olefinic comonomer, or to the olefinic monomer having at least twodouble bonds, to activate the free radical mechanism.
 6. A method as inclaim 1, wherein polymerizing the monomers occurs within less than orequal to 5 seconds.
 7. A method as in claim 1, further comprisingforming an ion conductive layer on the electroactive layer.
 8. A methodas in claim 7, wherein the ion conductive layer is positioned betweenthe electroactive layer and the layer comprising the polymer.
 9. Amethod as in claim 7, comprising depositing the monomer and thecomonomer on a surface of the ion conductive layer.
 10. A method as inclaim 1 wherein the electron donating group comprises at least one groupselected from the group consisting of an alkylamino, a heteroaryl, acycloalkyl, a cycloalkenyl, a cycloalkynyl, —OCOR₂, —NR₂COR₂, —OR₂,—SR₂, —Si(OR₂)₃, —Si(OR₂)₂H, —Si(OR₂)H₂, —Si(R₂)₃, —Si(R₂)₂H, —Si(R₂)H₂,

and wherein each occurrence of R₂ is independently selected from thegroup consisting of hydrogen; substituted or unsubstituted, branched orunbranched aliphatic; substituted or unsubstituted cyclic; substitutedor unsubstituted, branched or unbranched acyclic; substituted orunsubstituted, branched or unbranched heteroaliphatic; substituted orunsubstituted, branched or unbranched acyl; substituted or unsubstitutedaryl; substituted or unsubstituted heteroaryl; substituted orunsubstituted, branched or unbranched alkylene oxide or poly(alkyleneoxide); a metal ion; an anionic group; and a lithium-containing group;wherein n is 1, 2 or 3; and wherein R₂ may optionally be linked to atleast one further electron donating or electron withdrawing groupattached to an olefinic double bond.
 11. A method as in claim 1, whereina molar ratio of the olefinic monomer comprising at least one electronwithdrawing group to the at least one olefinic comonomer comprising atleast one electron donating group is approximately one to one.
 12. Amethod as in claim 1, wherein a molar ratio of double bonds attached tothe olefinic monomer comprising at least one electron withdrawing groupto double bonds attached to the at least one olefinic comonomercomprising at least one electron donating group is approximately one toone.
 13. A method as in claim 1, wherein the electron withdrawing groupis attached to a double bond.
 14. A method as in claim 13, wherein theelectron donating group is attached to a double bond.
 15. A method as inclaim 1, wherein R₁ may be linked to at least one further electrondonating or electron withdrawing group attached to an olefinic doublebond.
 16. A method as in claim 1, wherein the olefinic monomer isN-phenyl maleimide or N-triethylene glycol maleimide, and the olefiniccomonomer is diethylene glycol divinyl ether, triethylene glycol divinylether, or 1,4-cyclohexanedimethanoldivinylether.
 17. A method forforming a component for use in an electrochemical cell, the methodcomprising: providing an electroactive layer; depositing a monomercomprising a maleimide which includes at least one double bond and atleast one electron withdrawing group, and a comonomer comprising a vinylether, on a surface of the electroactive layer, wherein the comonomer isdifferent than the monomer comprising the maleimide; wherein theelectron withdrawing group is selected from the group consisting ofCON(R₁)₂ and —CONR₁H; wherein two electron withdrawing groups attachedin the 1,2-position to the double bond may form together with the doublebond of a 5- to 6-membered substituted or unsubstituted, unsaturatedcycle or heterocycle; wherein R₁ may be linked to at least one furtherelectron donating or electron withdrawing group; and wherein eachoccurrence of R₁ is independently selected from the group consisting ofhydrogen; halogen; substituted or unsubstituted, branched or unbranchedacyl; substituted or unsubstituted aryl; substituted or unsubstitutedheteroaryl; a metal ion, and a lithium-containing group; andpolymerizing the monomer and comonomer using a free radical mechanism toform a polymer, wherein the polymer includes structural units comprisingthe at least one electron withdrawing group that alternate withstructural units comprising at least one electron donating group,wherein a gel state ion conductivity of the polymer is greater than orequal to 10⁻⁴ S/cm.
 18. A method as in claim 17, wherein the electronwithdrawing group is attached to a double bond.
 19. A method as in claim18, wherein R₁ may be linked to at least one further electron donatingor electron withdrawing group attached to an olefinic double bond.
 20. Amethod as in claim 17, wherein the olefinic monomer is N-phenylmaleimide or N-triethylene glycol maleimide, and the olefinic comonomeris diethylene glycol divinyl ether, triethylene glycol divinyl ether, or1,4-cyclohexanedimethanoldivinylether.